> [!abstract] Summary
> **Karma shader reference** — MTLX (MaterialX) shader properties used most often: **Thin Walled** (for very thin glass / bubbles, single-sided geometry, lit-from-behind translucency), **Karma Ramp** (needs an MTLX Position input via MTLX Extract), **MTLX Modulo** for repeating patterns, **Primvar Reader** for attribute-driven shading, plus material-builder and turntable references.
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# Shader Properties
## Thin Walled
- Use for **very thin glass, bubbles, and any single-sided geometry** — no internal volume / refraction artefacts.
- **Translucency effect:** Thin Walled also provides the effect of a translucent object being **lit from behind** — the shading point is "lit" by the specified fraction of the light hitting the reverse side of the object at that point.
- **Recommended only for thin objects (single-sided geometry).** Objects with real thickness may render incorrectly.
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- **Thin Walled** is ideal for thin (single-sided) objects, like bubbles for example.
-  — Without
-  — With
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# Color Nodes
- **Ramp** — use **Karma Ramp Parameter**. Needs an **MTLX Position** input connected via an **MTLX Extract** node.
- ![[file-20241117174607560.png|550]]
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# Math Nodes
- **MTLX Modulo** — useful for **repeating patterns** (tiling, periodic masks, stripes).
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# Attribute Nodes
- **Primvar Reader** — read any primvar (custom attribute) from the geometry into the shader. Essential for per-instance variation, custom masks, per-face values.
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# Material Builder
- [[../../../../OUT OF PUBLISH/PIPE 2026 - ARTFX LILLE/KARMA/Karma Material builder|Karma Material Builder]] *(private legacy)*.
- See also [[KARMA Auto material Builder|KARMA Auto Material Builder]] for the auto-build flow.
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# Turntable Setup
- [Procedural Lookdev HDA — Reddit](https://www.reddit.com/r/vfx/comments/16k4y0k/wip2_free_procedural_lookdev_hda_houdini_karma/?tl=fr)
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# 🔗 Related
- [[../KARMA MOC|KARMA MOC]].
- [[KARMA Auto material Builder|KARMA Auto Material Builder]].
- [[KARMA Displacement|KARMA Displacement]].
- [[KARMA MIPMAP|KARMA MIPMAP]] — texture optimisation in shaders.
- [[../../SOLARIS/LOOKDEV HOUDINI SOLARIS|LOOKDEV HOUDINI SOLARIS]] — Solaris-side lookdev context.