# Introduction to glTF and Physically Based Rendering for 3D Artists

> What glTF is, why it is called the JPEG of 3D, and what physically based rendering asks of an artist. The lecture walks through the metallic-roughness material maps one at a time: base color, metallic, roughness, normal, occlusion and emissive. It shows how roughness spreads a reflection, and closes with three practical habits for painting and packing textures that look right in any glTF viewer.

- Canonical watch page: [Introduction to glTF and Physically Based Rendering for 3D Artists](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists)
- Publisher: [Academa, Inc.](https://academa.ai)
- Subject: Computer Science
- Published: 2026-10-05T16:08:18.957Z
- Updated: 2026-10-05T16:08:18.957Z
- Duration: PT139S (2 minutes 19 seconds)
- Chapters: 2
- Views: 4
- Language: en-US
- Access: Free
- Video stream: [HLS content](https://academa.ai/media/l/01M46CHHKH6ESNHKV1BYEQJAP5/0/dark/master.m3u8)
- Embed: [Player](https://academa.ai/embed/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists)
- Audiovisual record: [Semantic JSON](https://academa.ai/media/l/01M46CHHKH6ESNHKV1BYEQJAP5/0/semantic.json)
- Thumbnail: [Image](https://academa.ai/media/l/01M46CHHKH6ESNHKV1BYEQJAP5/0/dark/poster.jpg)

## Description

A short, artist-friendly introduction to glTF and PBR: base color, metallic, roughness, normal, occlusion and emissive maps.

## Chapters

- [00:00–00:45.879 · One File, Real Materials](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=0)
- [00:45.879–02:19 · The Material Maps](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=45.87941666666666)

## Transcript

### [00:00 · One File, Real Materials](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=0)

You have finished a model, and you want it to look right in a web browser, a game engine, and a client's viewer. That is the job G L T F was made for. It packs your mesh, your materials, and your textures into one tidy file. That is why people call it the JPEG of three D: compact, standard, and ready to display anywhere. Its materials follow an idea called physically based rendering, or P B R. Instead of painting how a surface looks under one light, you describe what the surface is made of. Then the renderer handles the light. Move the lamp, and the reflection moves with it, worked out for you. The same material behaves believably at noon, at dusk, or in a dark room.

### [00:45.879 · The Material Maps](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=45.87941666666666)

G L T F describes that material with a small set of maps, called the metallic roughness workflow. Here they are, beside a lit surface we can adjust. Base color is the pure color of the surface, with no shadows or highlights painted in. Metallic says whether it is metal. Zero for paint, plastic, wood or skin, and one for bare metal. Most surfaces are simply one or the other. Roughness controls how blurry reflections are. At zero the surface is glossy, and the reflection is one sharp beam. Raise it, and the light scatters into a soft, matte spread. A normal map fakes small bumps and scratches without adding geometry. Occlusion darkens the crevices where light struggles to reach. And emissive marks the parts that glow on their own, like screens or lamps. A few habits keep these maps honest. First, keep base color clean. Lighting belongs to the renderer, so do not bake shadows into it. Second, think in clear choices. Metal is metal and paint is paint; save the in between values for dust, rust, and worn edges. Third, know the packing. G L T F reads roughness from the green channel and metallic from the blue channel of one image, and occlusion usually fills the red. So export them together. Paint what the surface is, let the light do the rest, and your model will look right wherever G L T F takes it.

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## Complete audiovisual record

Immutable source: [semantic.json](https://academa.ai/media/l/01M46CHHKH6ESNHKV1BYEQJAP5/0/semantic.json)

Record version: 1. Render attempt: 0.

### How to read this timeline

Each scene owns its object identifiers. A beat's board is the complete board when listed, empty when marked empty, and unchanged from the nearest earlier listed board in the same scene when marked unchanged. Action times are absolute positions in the published video.

### Scene 1: [One File, Real Materials](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=0)

Span: 00:00–00:45.879 (0s–45.87941666666666s).

#### Objects

- box: a Polygon \[blue\] labelled "upright("glTF")" drawn in diagram (vertices=((4.0, 3.0), (6.0, 3.0), (6.0, 5.0), (4.0, 5.0)))
- caption: a Tex \[text\] that says "Mesh, materials and textures, in one file."
- definition: a Panel that says "Describe what a surface is made of. The renderer works out how light behaves on it."
- diagram: a Figure (x\_range=(0.0, 10.0), y\_range=(0.0, 8.0))
- engines: a Point \[text\] labelled "upright("engines")" drawn in diagram (location=(8.6, 1.5), show\_marker=False)
- heading\_file: a Heading that says "glTF: the JPEG of 3D"
- heading\_pbr: a Heading that says "Physically Based Rendering"
- in\_mat: a Vector \[gray\] drawn in diagram (start=(1.8, 4.0), end=(3.9, 4.0))
- in\_mesh: a Vector \[gray\] drawn in diagram (start=(1.8, 6.3), end=(3.9, 4.6))
- in\_tex: a Vector \[gray\] drawn in diagram (start=(1.8, 1.7), end=(3.9, 3.4))
- lamp: a Point \[yellow\] labelled "upright("light")" drawn in light\_fig (location=((5.0 - (4.0 \* sin(theta))), (1.0 + (4.0 \* cos(theta)))))
- light\_fig: a Figure (x\_range=(0.0, 10.0), y\_range=(0.0, 6.0))
- materials: a Point \[text\] labelled "upright("materials")" drawn in diagram (location=(1.2, 4.0), show\_marker=False)
- mesh: a Point \[text\] labelled "upright("mesh")" drawn in diagram (location=(1.2, 6.5), show\_marker=False)
- out\_eng: a Vector \[green\] drawn in diagram (start=(6.1, 3.6), end=(8.2, 1.8))
- out\_web: a Vector \[green\] drawn in diagram (start=(6.1, 4.4), end=(8.2, 6.2))
- ray\_in: a Vector \[yellow\] drawn in light\_fig (start=((5.0 - (4.0 \* sin(theta))), (1.0 + (4.0 \* cos(theta)))), end=(5.0, 1.0))
- ray\_out: a Vector \[red\] drawn in light\_fig (start=(5.0, 1.0), end=((5.0 + (4.0 \* sin(theta))), (1.0 + (4.0 \* cos(theta)))))
- slab: a Polygon \[blue\] labelled "upright("material")" drawn in light\_fig (vertices=((0.5, 0.3), (9.5, 0.3), (9.5, 1.0), (0.5, 1.0)))
- textures: a Point \[text\] labelled "upright("textures")" drawn in diagram (location=(1.2, 1.5), show\_marker=False)
- theta: a VariableNumber (initial\_value=0.7)
- web: a Point \[text\] labelled "upright("web")" drawn in diagram (location=(8.6, 6.5), show\_marker=False)

#### Beats

##### [00:00](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=0)

Narration: You have finished a model, and you want it to look right in a web browser, a game engine, and a client's viewer. That is the job G L T F was made for.

Board: Empty.

Actions:
- [00:00](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=0): heading\_file is shown on the screen, written out.
- [00:00](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=0): diagram is shown on the screen, written out.
- [00:0.8](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=0.8): mesh is shown on the screen, written out.
- [00:3.2](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=3.2): web is shown on the screen, written out.
- [00:4.44](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=4.44): engines is shown on the screen, written out.
- [00:7.44](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=7.44): box is shown on the screen, written out.

##### [00:9.76](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=9.76)

Narration: It packs your mesh, your materials, and your textures into one tidy file. That is why people call it the JPEG of three D: compact, standard, and ready to display anywhere.

Board: diagram — a Figure (x\_range=(0.0, 10.0), y\_range=(0.0, 8.0)); heading\_file — a Heading that says "glTF: the JPEG of 3D"; mesh — a Point \[text\] labelled "upright("mesh")" drawn in diagram (location=(1.2, 6.5), show\_marker=False); web — a Point \[text\] labelled "upright("web")" drawn in diagram (location=(8.6, 6.5), show\_marker=False); engines — a Point \[text\] labelled "upright("engines")" drawn in diagram (location=(8.6, 1.5), show\_marker=False); box — a Polygon \[blue\] labelled "upright("glTF")" drawn in diagram (vertices=((4.0, 3.0), (6.0, 3.0), (6.0, 5.0), (4.0, 5.0)))

Actions:
- [00:10.68](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=10.68): in\_mesh is shown on the screen, written out.
- [00:11.48](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=11.48): materials is shown on the screen, written out.
- [00:11.48](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=11.48): in\_mat is shown on the screen, written out.
- [00:12.36](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=12.36): textures is shown on the screen, written out.
- [00:12.36](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=12.36): in\_tex is shown on the screen, written out.
- [00:16.2](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=16.200000000000003): caption is shown on the screen, written out.
- [00:18.08](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=18.08): out\_web is shown on the screen, written out.
- [00:18.84](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=18.839999999999996): out\_eng is shown on the screen, written out.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): caption is hidden from the screen — left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): diagram is hidden from the screen — left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): mesh is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): web is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): engines is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): box is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): in\_mesh is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): materials is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): in\_mat is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): textures is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): in\_tex is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): out\_web is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): out\_eng is hidden from the screen — diagram left the board.
- [00:21.34](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=21.34): heading\_file is hidden from the screen — left the board.

##### [00:22.54](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=22.54)

Narration: Its materials follow an idea called physically based rendering, or P B R. Instead of painting how a surface looks under one light, you describe what the surface is made of.

Board: Empty.

Actions:
- [00:22.54](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=22.54): heading\_pbr is shown on the screen, written out.
- [00:24.68](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=24.68): definition is shown on the screen, written out.
- [00:30.84](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=30.84): definition (the "what a surface is made of" part) is emphasized.

##### [00:33.64](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=33.64)

Narration: Then the renderer handles the light. Move the lamp, and the reflection moves with it, worked out for you. The same material behaves believably at noon, at dusk, or in a dark room.

Board: definition — a Panel that says "Describe what a surface is made of. The renderer works out how light behaves on it."; heading\_pbr — a Heading that says "Physically Based Rendering"

Actions:
- [00:33.64](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=33.64): light\_fig is shown on the screen, written out.
- [00:33.64](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=33.64): slab is shown on the screen, written out.
- [00:33.64](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=33.64): definition (the "what a surface is made of" part) is no longer emphasized.
- [00:35.36](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=35.36): lamp is shown on the screen, written out.
- [00:35.36](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=35.36): ray\_in is shown on the screen, written out.
- [00:35.892](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=35.89242769500437): ray\_out is shown on the screen, written out.
- [00:36.08](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=36.08): lamp is redrawn as the numbers it depends on change.
- [00:36.08](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=36.08): ray\_in is redrawn as the numbers it depends on change.
- [00:36.08](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=36.08): ray\_out is redrawn as the numbers it depends on change.
- [00:36.08](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=36.08): theta ticks to 0.12.
- [00:40.24](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=40.239999999999995): slab is indicated — a transient flash.
- [00:41.92](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=41.92): lamp is redrawn as the numbers it depends on change.
- [00:41.92](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=41.92): ray\_in is redrawn as the numbers it depends on change.
- [00:41.92](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=41.92): ray\_out is redrawn as the numbers it depends on change.
- [00:41.92](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=41.92): theta ticks to 1.0.
- [00:44.838](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=44.83775): definition is hidden from the screen — left the board.
- [00:44.838](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=44.83775): heading\_pbr is hidden from the screen — left the board.
- [00:44.838](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=44.83775): light\_fig is hidden from the screen — left the board.
- [00:44.838](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=44.83775): slab is hidden from the screen — light\_fig left the board.
- [00:44.838](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=44.83775): lamp is hidden from the screen — light\_fig left the board.
- [00:44.838](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=44.83775): ray\_in is hidden from the screen — light\_fig left the board.
- [00:44.838](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=44.83775): ray\_out is hidden from the screen — light\_fig left the board.

### Scene 2: [The Material Maps](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=45.87941666666666)

Span: 00:45.879–02:18.722 (45.87941666666666s–138.72210416666667s).

#### Objects

- fan: a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* -0.6) + 0.7)))), (1.0 + (3.2 \* cos…)
- fan\_2: a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* -0.3) + 0.7)))), (1.0 + (3.2 \* cos…)
- fan\_3: a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.0) + 0.7)))), (1.0 + (3.2 \* cos(…)
- fan\_4: a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.3) + 0.7)))), (1.0 + (3.2 \* cos(…)
- fan\_5: a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.6) + 0.7)))), (1.0 + (3.2 \* cos(…)
- heading\_maps: a Heading that says "The Metallic-Roughness Workflow"
- heading\_tips: a Heading that says "Habits That Keep Maps Honest"
- lamp2: a Point \[yellow\] labelled "upright("light")" drawn in rough\_fig (location=(2.423129251049236, 4.059368749137954))
- ray\_in2: a Vector \[yellow\] drawn in rough\_fig (start=(2.423129251049236, 4.059368749137954), end=(5.0, 1.0))
- reading: a Point \[text\] labelled "upright("roughness") = 0.0" drawn in rough\_fig (location=(5.5, 5.2), show\_marker=False)
- rough: a VariableNumber (format\_spec='.1f')
- rough\_fig: a Figure (x\_range=(0.0, 10.0), y\_range=(0.0, 6.0))
- slab2: a Polygon \[blue\] labelled "upright("surface")" drawn in rough\_fig (vertices=((0.5, 0.3), (9.5, 0.3), (9.5, 1.0), (0.5, 1.0)))
- table: a Table \[text\] that says "Map What you paint Base color pure color, no lighting Metallic 0 for paint, 1 for metal Roughness 0 glossy, 1 matte Normal small bumps, faked Occlusion shadow in crevices Emissive parts that glow" (rows=(('Map', 'What you paint'), ('Base color', 'pure color, no ligh…, header=True)
- tips: a Block \[text\] that says "Keep base color clean: no baked shadows. Metal is 0 or 1; in between is for dust and wear. Pack one image: occlusion in red, roughness in green, metallic in blue."

#### Beats

##### [00:45.879](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=45.87941666666666)

Narration: G L T F describes that material with a small set of maps, called the metallic roughness workflow. Here they are, beside a lit surface we can adjust.

Board: Empty.

Actions:
- [00:45.879](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=45.87941666666666): heading\_maps is shown on the screen, written out.
- [00:49.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=49.15941666666666): table is shown on the screen, written out.
- [00:53.399](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.39941666666665): rough\_fig is shown on the screen, written out.
- [00:53.399](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.39941666666665): slab2 is shown on the screen, written out.
- [00:53.676](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.67553434097752): lamp2 is shown on the screen, written out.
- [00:53.676](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.67553434097752): ray\_in2 is shown on the screen, written out.
- [00:53.676](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.67553434097752): fan is shown on the screen, written out.
- [00:53.676](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.67553434097752): fan\_2 is shown on the screen, written out.
- [00:53.676](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.67553434097752): fan\_3 is shown on the screen, written out.
- [00:53.676](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.67553434097752): fan\_4 is shown on the screen, written out.
- [00:53.676](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=53.67553434097752): fan\_5 is shown on the screen, written out.

##### [00:55.919](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=55.919416666666656)

Narration: Base color is the pure color of the surface, with no shadows or highlights painted in.

Board: rough\_fig — a Figure (x\_range=(0.0, 10.0), y\_range=(0.0, 6.0)); heading\_maps — a Heading that says "The Metallic-Roughness Workflow"; slab2 — a Polygon \[blue\] labelled "upright("surface")" drawn in rough\_fig (vertices=((0.5, 0.3), (9.5, 0.3), (9.5, 1.0), (0.5, 1.0))); lamp2 — a Point \[yellow\] labelled "upright("light")" drawn in rough\_fig (location=(2.423129251049236, 4.059368749137954)); ray\_in2 — a Vector \[yellow\] drawn in rough\_fig (start=(2.423129251049236, 4.059368749137954), end=(5.0, 1.0)); fan — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* -0.6) + 0.7)))), (1.0 + (3.2 \* cos…); fan\_2 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* -0.3) + 0.7)))), (1.0 + (3.2 \* cos…); fan\_3 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.0) + 0.7)))), (1.0 + (3.2 \* cos(…); fan\_4 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.3) + 0.7)))), (1.0 + (3.2 \* cos(…); fan\_5 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.6) + 0.7)))), (1.0 + (3.2 \* cos(…)

Actions:
- [00:55.919](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=55.919416666666656): table is shown on the screen, written out.
- [00:57.999](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=57.999416666666654): slab2 is indicated — a transient flash.

##### [01:1.679](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=61.679416666666654)

Narration: Metallic says whether it is metal. Zero for paint, plastic, wood or skin, and one for bare metal. Most surfaces are simply one or the other.

Board: Unchanged from the preceding beat in this scene.

Actions:
- [01:1.679](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=61.679416666666654): table is shown on the screen, written out.
- [01:4.119](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=64.11941666666667): table (the "0 for paint" part) is indicated — a transient flash.
- [01:7.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=67.47941666666665): table (the "1 for metal" part) is indicated — a transient flash.

##### [01:12.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=72.15941666666666)

Narration: Roughness controls how blurry reflections are. At zero the surface is glossy, and the reflection is one sharp beam. Raise it, and the light scatters into a soft, matte spread.

Board: Unchanged from the preceding beat in this scene.

Actions:
- [01:12.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=72.15941666666666): table is shown on the screen, written out.
- [01:15.759](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=75.75941666666665): reading is shown on the screen, written out.
- [01:18.959](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=78.95941666666666): fan is indicated — a transient flash.
- [01:18.959](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=78.95941666666666): fan\_2 is indicated — a transient flash.
- [01:18.959](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=78.95941666666666): fan\_3 is indicated — a transient flash.
- [01:18.959](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=78.95941666666666): fan\_4 is indicated — a transient flash.
- [01:18.959](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=78.95941666666666): fan\_5 is indicated — a transient flash.
- [01:20.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=80.15941666666666): fan is redrawn as the numbers it depends on change.
- [01:20.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=80.15941666666666): fan\_2 is redrawn as the numbers it depends on change.
- [01:20.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=80.15941666666666): fan\_4 is redrawn as the numbers it depends on change.
- [01:20.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=80.15941666666666): fan\_5 is redrawn as the numbers it depends on change.
- [01:20.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=80.15941666666666): reading is redrawn as the numbers it depends on change.
- [01:20.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=80.15941666666666): rough ticks to 1.0.

##### [01:24.579](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=84.57941666666666)

Narration: A normal map fakes small bumps and scratches without adding geometry. Occlusion darkens the crevices where light struggles to reach. And emissive marks the parts that glow on their own, like screens or lamps.

Board: rough\_fig — a Figure (x\_range=(0.0, 10.0), y\_range=(0.0, 6.0)); heading\_maps — a Heading that says "The Metallic-Roughness Workflow"; slab2 — a Polygon \[blue\] labelled "upright("surface")" drawn in rough\_fig (vertices=((0.5, 0.3), (9.5, 0.3), (9.5, 1.0), (0.5, 1.0))); lamp2 — a Point \[yellow\] labelled "upright("light")" drawn in rough\_fig (location=(2.423129251049236, 4.059368749137954)); ray\_in2 — a Vector \[yellow\] drawn in rough\_fig (start=(2.423129251049236, 4.059368749137954), end=(5.0, 1.0)); fan — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* -0.6) + 0.7)))), (1.0 + (3.2 \* cos…); fan\_2 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* -0.3) + 0.7)))), (1.0 + (3.2 \* cos…); fan\_3 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.0) + 0.7)))), (1.0 + (3.2 \* cos(…); fan\_4 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.3) + 0.7)))), (1.0 + (3.2 \* cos(…); fan\_5 — a Vector \[red\] drawn in rough\_fig (start=(5.0, 1.0), end=((5.0 + (3.2 \* sin(((rough \* 0.6) + 0.7)))), (1.0 + (3.2 \* cos(…); reading — a Point \[text\] labelled "upright("roughness") = 0.0" drawn in rough\_fig (location=(5.5, 5.2), show\_marker=False)

Actions:
- [01:24.919](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=84.91941666666666): table is shown on the screen, written out.
- [01:29.319](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=89.31941666666665): table is shown on the screen, written out.
- [01:33.319](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=93.31941666666665): table is shown on the screen, written out.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): heading\_maps is hidden from the screen — left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): rough\_fig is hidden from the screen — left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): slab2 is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): lamp2 is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): ray\_in2 is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): fan is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): fan\_2 is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): fan\_3 is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): fan\_4 is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): fan\_5 is hidden from the screen — rough\_fig left the board.
- [01:37.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=97.47941666666665): reading is hidden from the screen — rough\_fig left the board.

##### [01:38.679](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=98.67941666666667)

Narration: A few habits keep these maps honest.

Board: Empty.

Actions:
- [01:38.679](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=98.67941666666667): heading\_tips is shown on the screen, written out.
- [01:39.399](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=99.39941666666664): tips is shown on the screen, written out.

##### [01:41.919](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=101.91941666666666)

Narration: First, keep base color clean. Lighting belongs to the renderer, so do not bake shadows into it.

Board: tips — a Block \[text\] that says "Keep base color clean: no baked shadows. Metal is 0 or 1; in between is for dust and wear. Pack one image: occlusion in red, roughness in green, metallic in blue."; heading\_tips — a Heading that says "Habits That Keep Maps Honest"

Actions:
- [01:42.159](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=102.15941666666666): tips (the "Keep base color clean" part) is emphasized.
- [01:43.199](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=103.19941666666665): table is indicated — a transient flash.

##### [01:49.479](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=109.47941666666667)

Narration: Second, think in clear choices. Metal is metal and paint is paint; save the in between values for dust, rust, and worn edges.

Board: Unchanged from the preceding beat in this scene.

Actions:
- [01:49.719](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=109.71941666666666): tips (the "Keep base color clean" part) is no longer emphasized.
- [01:49.719](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=109.71941666666666): tips (the "Metal is 0 or 1" part) is emphasized.
- [01:52.359](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=112.35941666666666): table is indicated — a transient flash.

##### [01:59.439](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=119.43941666666666)

Narration: Third, know the packing. G L T F reads roughness from the green channel and metallic from the blue channel of one image, and occlusion usually fills the red. So export them together.

Board: Unchanged from the preceding beat in this scene.

Actions:
- [01:59.599](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=119.59941666666666): tips (the "Metal is 0 or 1" part) is no longer emphasized.
- [01:59.599](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=119.59941666666666): tips (the "Pack one image" part) is emphasized.
- [02:3.359](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=123.35941666666666): tips (the "Pack one image" part) is no longer emphasized.
- [02:3.359](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=123.35941666666666): tips (the "roughness in green" part) is emphasized.
- [02:5.119](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=125.11941666666667): tips (the "metallic in blue" part) is emphasized.
- [02:5.119](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=125.11941666666667): tips (the "roughness in green" part) is no longer emphasized.
- [02:8.319](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=128.31941666666665): tips (the "metallic in blue" part) is no longer emphasized.
- [02:8.319](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=128.31941666666665): tips (the "occlusion in red" part) is emphasized.
- [02:10.839](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=130.83941666666666): tips (the "occlusion in red" part) is no longer emphasized.

##### [02:11.439](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=131.43941666666666)

Narration: Paint what the surface is, let the light do the rest, and your model will look right wherever G L T F takes it.

Board: Unchanged from the preceding beat in this scene.

Actions:
- [02:17.68](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=137.68043749999998): heading\_tips is hidden from the screen — left the board.
- [02:17.68](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=137.68043749999998): table is hidden from the screen — left the board.
- [02:17.68](https://academa.ai/@echadwick-artist/lectures/introduction-to-gltf-and-physically-based-rendering-for-3d-artists?t=137.68043749999998): tips is hidden from the screen — left the board.