Translates a product's materials into optical behavior - bright-field or dark-field schemes for glass, anisotropic highlight streaks aligned with brushed-metal grain, raking light at 10-30 degrees for leather and fabric, designed 2-3-shape environments for chrome - so each surface carries the highlight signature the eye expects from that material. Use when someone asks "how do I photograph glass so it doesn't look like a blob", "how do I make brushed aluminum look real in a render", "why does my product look like cheap plastic in photos", "how should I light leather so the texture shows", or when a material reads fake even though the shape is correct. Do NOT use for the overall rig plan - use studio-lighting-design instead; to phrase materials for an image model, use photoreal-prompt-craft.
---
name: material-rendering-direction
description: Translates a product's materials into optical behavior - bright-field or dark-field schemes for glass, anisotropic highlight streaks aligned with brushed-metal grain, raking light at 10-30 degrees for leather and fabric, designed 2-3-shape environments for chrome - so each surface carries the highlight signature the eye expects from that material. Use when someone asks "how do I photograph glass so it doesn't look like a blob", "how do I make brushed aluminum look real in a render", "why does my product look like cheap plastic in photos", "how should I light leather so the texture shows", or when a material reads fake even though the shape is correct. Do NOT use for the overall rig plan - use studio-lighting-design instead; to phrase materials for an image model, use photoreal-prompt-craft.
---
# material-rendering-direction
Material perception runs almost entirely on specular behavior - get the highlight signature wrong and the brain reports "cheap plastic" even when the shape is perfect. A wrong angle can be recomposed; a wrong material scheme means reshooting or re-rendering the entire campaign because the aluminum streak ran across the grain. This skill translates each named material into the one lighting scheme its physics demands, as an addendum to the rig plan.
## Operating procedure
Run the steps in order: identify before scheme, scheme before values. The material class fixes the scheme, and the scheme fixes which numbers exist to set - values chosen before classification are guesses wearing precision.
### Step 1: Elicit the bill of materials and the charter
Ask for the client's charter first - the grade contract locks against its brand colors. Paste the charter block if one exists. If the client has a charter but the foundations pack is not installed, elicit the needed values directly and label them provisional. If no charter exists at all, halt and route to premium-design-foundations - never substitute worked-example values. Then gather:
- **Materials**: every visible material by name - brushed aluminum, soda-lime glass, full-grain leather, soft-touch plastic, chrome, fabric weave. If the user can only say "metal", ask brushed or polished - the schemes are opposites.
- **Finish direction** per material: brushing grain, weave direction.
- **Surface map**: which surfaces from the studio-lighting-design rig plan carry each material.
- **Output path**: photo, 3D render, or prompt spec. Default execution when no studio exists: photoreal-prompt-craft, so a picture still comes out the other end.
If any input is a guess, label it a guess and move on.
### Step 2: Classify each material into its scheme