在2D项目中使用3D功能遇问题：平面层级覆盖异常

Hey Olivier, no worries at all about this being your first question—we’ve all stumbled through our first 2D/3D hybrid project hurdles! Let’s walk through the most common fixes for the occlusion problem you’re seeing where a plane that should be hidden is always rendering on top.

Likely Causes & Fixes #

• Verify Z-Axis Positioning
  In 3D space, object occlusion depends on their distance from the camera along the Z-axis. Double-check the Transform component of all three planes:

  • If using a perspective camera, the plane that should be behind should have a larger Z value (further from the camera) than the middle plane you’re rotating. For example, if the middle plane is at Z=0, the back plane should be at Z=1, and the front at Z=-1.
  • If using an orthographic camera, ensure all planes fall within the camera’s Clipping Planes (Near/Far values) and their Z positions are ordered correctly relative to each other.

• Check Material Render Queue
  Open the material applied to your planes and look at the Render Queue setting. If one plane’s material has a lower queue number (higher priority, e.g., Transparent instead of Geometry), it will render before others regardless of Z depth. Make sure all three planes use the same render queue (default Geometry is ideal for opaque planes).

• Ensure Depth Testing is Enabled
  Some custom shaders or modified materials disable depth testing, which tells the engine to ignore Z-axis occlusion. Check your shader’s settings:

  • For most default engine shaders, this is set correctly, but if you’re using a custom shader, confirm the ZTest property is set to LEqual (not Always).

• Camera Settings for 2D/3D Hybrid
  Since you’re working in a 2D project, the default camera might be configured for 2D sprites. Adjust these settings:

  • Confirm the camera’s Projection mode is set appropriately (perspective for true 3D depth, orthographic if you want flat 3D placement).
  • Ignore 2D-specific Sorting Layer settings—they don’t apply to 3D objects, so rely solely on Z-axis positioning for occlusion.

• Layer & Culling Mask Check
  Make sure all three planes are assigned to a layer that’s included in your camera’s Culling Mask. If one plane is on a layer the camera isn’t rendering, it might behave unexpectedly (though this is less likely to cause occlusion issues, it’s worth ruling out).

If none of these fixes resolve the issue, sharing a bit more context—like which engine you’re using, the exact shader/material type, or camera settings—would help narrow things down further.

内容的提问来源于stack exchange，提问作者Olivier Pons