Displacement mapping, in some scenarios, could use extra memory and increase the render time significantly. Depending on the displacement settings, image resolution and object being displaced, V-Ray could generate very heavy geometry that would be difficult to render. Read on to find out how to identify and resolve such issues.
Common signs of displacement issues:
- 3D host application freezes or crashes, especially when rendering high-resolution images.
- Endless calculation of the Light Cache
- Render stuck while compiling scene geometry or building Embree static accelerator
- Memory utilization reaches 100%
How to know if it is a displacement issue?
Some 3D host applications have an option for disabling the displacement globally. This can be handy when you are not sure if the displacement is causing the issue.
- 3ds Max
- Revit - there is a way to override the displacement but all the materials need to be overridden. The option Keep Relief Pattern in the Global Overrides Tab disables the Bump and the Displacement.For more information, visit Global Overrides Tab - V-Ray 5 for Revit - Chaos Help.
- Disable the displacement not visible in the render. The displacement that is present in the camera view, but is hidden behind other geometry, is still calculated and consumes RAM. Disable it.
- Apply displacement only where it is needed in your scene. Since displacement consumes a lot of memory, you should use it wisely and avoid it on large scene areas.
- Increase Edge length. Setting a lower value of Edge Length produces more detailed geometry but uses more RAM. Increase the Edge Length parameter to save memory. For more information see the Edge Length Example..
- Decrease Max subdivs. This works with the Subdivision type. The Max subdivs value controls the maximum sub-triangles generated from any triangle of the original mesh. Decreasing this value saves memory.
- Replace with Bump or Normal mapping. In some scenarios, displacement can be replaced with a Bump or Normal Map which is less memory-consuming.
- Use a machine with more RAM available.