Transparency
Transparent materials allow you to see through a mesh. Transparency can be partial (e.g. glass) or binary (fully visible or fully invisible per pixel). Choosing the correct method is important for both visual quality and performance.
There are two main approaches:
Transparent Blending
Enable transparency by setting the material’s Transparent toggle to Yes. The final pixel color is blended with what has already been rendered behind it, using a blend mode (e.g. alpha blending).
Pros
Supports partial transparency (smooth transitions between opaque and transparent)
Ideal for materials like glass, water, smoke, and UI elements
Cons
Requires correct rendering order (back-to-front sorting). Incorrect order can cause visible artifacts
Performance cost: Objects behind must still be rendered even if fully covered
Can produce visual errors when transparent objects overlap or intersect
Use when
You need smooth, semi-transparent effects
Visual accuracy is more important than performance
Alpha Testing (Cutout)
Alpha testing uses a threshold to decide whether a pixel is rendered or discarded.
Example: If the alpha threshold is 0.1, pixels with alpha < 0.1 are discarded; others are fully opaque.
Pros
No sorting issues (renders like opaque objects)
Better performance than blending in many cases
Works well with depth testing and shadows
Cons
No partial transparency (hard cut between visible/invisible)
Can produce jagged or pixelated edges
Tips
Adjust the threshold to minimize harsh edges
Use higher-resolution textures or dithering techniques to improve appearance
Use when
You need sharp cutouts (foliage, fences, grates)
Performance and stability are important
Quick Comparison
Partial transparency
✅ Yes
❌ No
Sorting required
⚠️ Yes
❌ No
Performance
❌ Higher cost
✅ Lower cost
Edge quality
✅ Smooth
⚠️ Hard edges
Rule of Thumb
Use Transparent Blending for glass, liquids, effects
Use Alpha Test for foliage, cutout textures, thin geometry
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