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Module 2 • Lesson 3🧵 Surfaces & 3D

The last integration frontier is dimension. A graphic must sink into a fabric's folds, glass must bend what's behind it, and a CGI render must arrive as separable light. Displacement maps, refraction, and multi-pass compositing turn flat overlays into things that live on real surfaces.

📚 What You'll Learn

By the end of this lesson, you will be able to:

  • Use a displacement map to wrap a graphic onto a textured surface's geometry
  • Blend the wrapped graphic so it picks up the surface's light and shadow
  • Fake glass and refraction — see-through with distortion and speculars
  • Understand a multi-pass CGI render (beauty, depth, AO, specular) and comp it
  • Tie it all to Module 1's blend math and 32-bit light

⏱️ Estimated Time: 60 minutes

🎯 Project (module deliverable): A graphic displaced convincingly onto a textured surface, plus a glass or render element integrated with it.

In This Lesson

👤 The Goal: On the Surface, Not On Top

The same logo on the same folded fabric. On the right, a flat decal — straight lines ignoring every crease, obviously pasted. On the left, a displacement map bends the logo along the folds and a blend lets the fabric's shadows fall across it, so it reads as printed into the cloth. Drag the handle:

Displaced Flat decal
A diagram of the principle. The fabric's own light and dark folds become a map that pushes the logo's pixels around, and a blend mode lets the cloth's shadows cross it — so it belongs to the surface.

🧠 Mental Model: Luminance Is Geometry

You have no 3D model of the fabric — but you don't need one, because the brightness of the surface already encodes its shape. Where cloth bulges toward the light it's bright; where it folds away it's dark. A displacement map reads that luminance and uses it to shove an overlay's pixels: bright areas push one way, dark the other, so the overlay deforms to follow geometry it can't see.

Displacement handles the shape; a blend mode handles the light. After displacing, set the graphic to Multiply (or Linear Burn) so the surface's shadows darken it in the folds, and it stops being an overlay and becomes part of the material. Two steps: deform, then shade.

Luminance map pushes pixels overlay deforms the surface's own brightness is the geometry — no 3D needed
Figure 1: A displacement map is just the surface's luminance. Its light/dark values offset the overlay's pixels, bending straight lines to ride the folds.

🗺️ The Displacement Map

The workflow: prepare the map, then displace against it. Make the map — duplicate the surface, desaturate, blur slightly (a few px, to smooth noise into shape), and save it as its own .psd. Displace the overlay — select the graphic layer and run Filter ▸ Distort ▸ Displace, set horizontal/vertical scale (start ~10), and choose that saved .psd. Then set the graphic to Multiply so the folds shade it.

Filter ▸ Distort ▸ Displace
Horizontal Scale 10 Vertical Scale 10 ✓Stretch To Fit ✓Repeat Edge Pixels Choose displacement map: fabric_map.psd → then set layer to Multiply
Figure 2: Displace reads a saved .psd map. Higher scale = more deformation; too much tears the graphic. After displacing, Multiply (or Linear Burn) lets the surface's shading fall across it.

⚠️ Blur the map, or you displace the noise

A displacement map should carry shape, not grain. If you skip the slight blur, every fabric fiber and sensor speck becomes a tiny offset and the graphic gets a jittery, chewed edge. Smooth the map to the folds you actually want to follow.

🔮 Glass, Refraction & Render Passes

Glass and refraction are the same idea aimed at transparency. A glass element shows what's behind it, distorted: copy the background behind the glass, displace or Filter ▸ Distort ▸ Glass it to bend the view, and add speculars and edge highlights on Screen. Real glass is mostly its edges, highlights, and the distortion — not a grey shape.

Integrating a CGI render is where Module 1 pays off. A render doesn't arrive as one picture but as passes — a beauty pass, plus depth, ambient occlusion, specular, and shadow passes, often as 32-bit EXR. You composite them: Multiply the AO for contact shadow, Screen/Add the specular for highlights, and use the depth pass to drive lens-blur DoF (Lesson 2.2). Working in 32-bit keeps the render's real light intact.

Depth → drives DoF Specular — Screen/Add AO — Multiply Beauty pass A render is separable light — recombine passes with the blend math from Module 1 (Multiply, Screen, Add) in 32-bit light.
Figure 3: A CGI render as passes. You are not "pasting a 3D object" — you are recombining its light with the same Multiply/Screen/Add math you learned in Module 1, which is what lets you match it to the plate.

✅ Everything in this module compounds

A fully integrated render gets the edge work (2.1), the capture match — grain, CA, DoF from its depth pass (2.2), and pass compositing in 32-bit (this lesson, and Module 1). Photoreal integration is never one trick; it's all of them, each removing one more tell.

🛠️ Guided Build: Wrap a Graphic

Grab a photo of a textured surface with clear folds or weave (fabric, a flag, a knitted jumper) and a logo or text to apply.

Step 1: Make the map · 8 min

  1. Duplicate the surface, Desaturate, apply a small Gaussian Blur (2–4 px) to keep shape and drop noise.
  2. Save it as its own surface_map.psd.

Step 2: Displace the graphic · 10 min

  1. Place your graphic, position it. Filter ▸ Distort ▸ Displace, scale ~10/10, choose surface_map.psd.
  2. Adjust scale until it follows the folds without tearing.

Step 3: Shade it into the material · 10 min

  1. Set the graphic to Multiply (or Linear Burn) so the fabric's shadows cross it; drop opacity slightly.
  2. Optionally add a mask to fade the graphic where the cloth turns steeply away.

Step 4: Add a glass or render element · 8 min

  1. For glass: copy the background behind it, Glass/Displace to distort, add Screen speculars and edge highlights.
  2. For a render: Multiply the AO, Screen the specular, drive DoF from the depth pass. Module 2 deliverable complete. 🏆

✅ Project Completion Checklist (Module 2 deliverable)

  • ☐ A blurred, desaturated displacement map saved as its own .psd
  • ☐ Graphic displaced to follow the surface without tearing
  • ☐ Graphic set to Multiply so folds shade it
  • ☐ A glass element (refraction + speculars) or a comped render pass
  • ☐ Edge + capture match from 2.1/2.2 applied to the result

🧗 Now You: Solo Variation

🌟 Your challenge

  1. Displace the same logo onto three surfaces — fabric, skin, and cracked earth — and tune the scale and blend for each material.
  2. Composite a drinking glass or bottle over a scene so the background bends through it and the rim catches a specular. Sell it with edges, not fill.
  3. If you have access to any render passes (even a free sample EXR), practice recombining beauty + AO + specular and driving DoF from depth.

Going further: chain displacement with a Smart Object so the graphic stays re-editable — change the artwork and re-run Displace to re-wrap it, a live mockup on a textured surface.

🍳 Recipe Card: Surfaces & 3D

Deform, shade, refract, recombine

  1. Map: duplicate surface → desaturate → slight blur → save as .psd
  2. Displace the graphic against the map (scale to taste, don't tear)
  3. Multiply the graphic so folds shade it into the material
  4. Glass: distort the background behind it + Screen speculars/edges
  5. Render: Multiply AO, Screen/Add specular, depth → DoF, in 32-bit

Mantra: brightness is geometry — let the surface's own light bend and shade what you lay on it.

📓 Learning Journal

Add to your journal after this lesson:

  • Key concepts you learned
  • Techniques that clicked for you
  • Questions or confusion points to revisit
  • Ideas you want to try
  • Your progress and feelings about learning this

✍️ This lesson's prompt: Where have you seen a "flat decal" mockup that broke the illusion? What would a displacement map and a Multiply have fixed?

📝 Module 2 Summary

🎓 Key Takeaways

  • A perfect mask makes a silhouette; edge work (defringe, light wrap, color bleed) makes a photograph.
  • Match the plate's optical signature — grain, noise, chromatic aberration, and depth of field.
  • Displacement maps use a surface's luminance as geometry to wrap graphics onto it.
  • Glass is distortion + speculars; a render is separable passes recombined with blend math in 32-bit.

🎉 What You've Accomplished — Across All of Module 2

You can now make an added element optically indistinguishable from the plate: its edge belongs, it shares the lens's signature, and it lives on real surfaces and in real dimension. This is the compositing that ads, films, and album covers are built on — and it rests directly on the color science of Module 1.

❓ Common Questions at This Stage

My displaced graphic looks warped but still "on top". Why?

You did the deform but not the shade. Displacement handles shape; you still need a blend mode (Multiply/Linear Burn) so the surface's shadows fall across the graphic. Shape without shading is only half the illusion.

Do I need a 3D app for the render parts?

Not to composite them — Photoshop recombines render passes beautifully with blend modes and 32-bit. You need a 3D app only to create the passes. Knowing how to comp them is the skill that makes you valuable on a CGI-heavy job.

🔭 Looking Ahead

You've made things belong to a scene. Next you make people flawless: Module 3 — Beauty & Product Retouching Mastery takes retouching from natural to agency-grade, and tackles the hardest surfaces of all — chrome, glass, and liquid.

✅ Before the Next Module

  • Fully integrate one composite through 2.1 → 2.2 → 2.3.
  • Wrap a graphic onto a real textured surface with a displacement map.
  • Write your Learning Journal entry.

📚 Additional Resources

🌟 Encouragement for the Journey

Photoreal compositing is equal parts science and patience — a dozen small, honest fixes that each remove one tell. You now know all of them. The next time a composite "just looks off", you'll be able to name exactly why and fix it. On to the human face.