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How To Avoid and Solve VRay Lighting Bugs and Artifacts

A Checklist To Keep In Mind

If you’ve ever experienced strange light bugs in your renders that you just couldn’t troubleshoot, then this tutorial is for you. The goal of this article is to provide you with an easy checklist that you can follow every time you begin a new project. Doing so will help you avoid lighting bugs like the disco lights and get error free renders. So let’s get to it then.

Lighting Bugs Checklist

  1. Always make sure that you’re not getting any errors/warnings in the VRay messages log. You can access the log from the VRay ‘Settings’ Tab with the ‘Show Log’ button. Errors like ‘Far from Origin’ or ‘Scene Bounding Box is too large’ mean you need to bring your scene close to the Origin Coordinates. Your scene should always be centered around the Origin.
  2. It’s important to make sure that you’re working in Real World Scale. This means that the dimensions of the objects in your scene should be the same as those in the real world. Setting your system and display units to centimeters or inches is a good standard. You can always use a tape measure helper to check the dimensions in your scene.
  3. Another aspect you need to consider is check all your Lights.
    1. 1. Your lights shouldn’t touch or intersect any geometry or even other lights in your scene.
    2. 2. If you’ve hidden any lights, you should be aware that these will still remain on and renderable. Uncheck the ‘Hidden Lights’ option in the VRay Global Switches rollout. This will instruct VRay not to render any hidden lights.
    3. 3. Lastly, check to see that there aren’t any duplicate lights overlapping each other.
  4. Also notice that Texturing issues might have a hand in causing these bugs. Take care of these points:
    1. 1. All your objects should have proper UVW Mapping applied to them.
    2. 2. Use the VRay Scene Converter to convert the 3ds Max Standard materials into compatible VRay Materials. If you’re using any Raytrace materials in your scene then you’ll have to manually convert these. The aim is to only work with material types officially supported by VRay.
    3. 3. By using the VRay Override material option, render your scene with a basic VRayMtl to see if it solves the lighting bugs. This way you can pinpoint the reason behind the artifacts.
  5. It’s a good idea to Delete Unnecessary Objects when you’re sure you won’t require them anymore.
    1. Instead of keeping objects hidden, delete them and reduce the clutter in your scene. You never know when you might accidently unhide something.
    2. When using DWG Plans, try not to extrude them for creating geometry. Only use them as snap guides and model from scratch.
    3. Sometimes while importing DWG files you also get unwanted scene objects, shapes or layers. Usually under the name ‘Block’, you should delete these if not required.
    4. After you’ve finalized your models, collapse the modifier stacks and convert all your meshes to Editable Poly.
  6. If everything else fails, try shifting all your scene assets into a new directory one by one. This will remove any rogue links and help you troubleshoot the cause in a precise manner.


If you still have any problems or doubts, you can always contact us for help on VRay School. Stay tuned for more tutorials and comment about your experiences with VRay bugs below. See you soon.

December 12, 2016
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