EricMBloggie

If you’ve ever tried using Digimation’s Speedtree plugin in V-Ray, you’ve undoubtedly run into major problems. They render painfully slow, there are blurry parts, flickering in animation– a world of trouble.

There has been a lot of discussion on nerdy forums as to whether or not Digimation’s SpeedTree plugin can be used in V-Ray. I’m here to tell you, they can. You just have to go through a little workaround to get them looking good.
Using Speedtrees with V-Ray

1. Set the Secondary Ray Bias to .001
   This makes it so the leaf planes don’t overlap, getting rid of the black splotches and flickering.
   
2. Convert Materials to V-Ray Materials.
   

   • The leaves are using Opacity maps to render, and V-Ray is much faster with rendering opacity maps in VRayMtl
   • If you don’t want to spend all of those mouse clicks doing this manually, you can automate the process.
     • Select all of your trees.
     • File –> Save Selected.
     • Open your tree file.
     • Right click on Viewport –> V-Ray Scene Converter (5th one up from the bottom of the right click menu
     • Save File
     • Go back to your original file
     • Delete the Non-VRayMtl Trees
     • File –> Merge // Merge in your newly converted trees.
   • Now for the manual labor. For some reason, V-Ray blurs the tree’s maps in an odd way, that creates weird blurry anomalies in the render. To combat this, you’ll have to tell V-Ray not to blur the tree’s textures.

   • Select the tree’s Shader in the Material Editor. It will be a Multi-Sub Object
     

   • Now go through BOTH the Diffuse and Opacity channels of each Sub-Material (Branches usually only have Diffuse) and do this:
     
   • Set the blur to 0.01. An easy way to do this is to Right-click the Spinner next to the number.
   • Set the Filtering to ‘None’

3. Done!

With the Secondary Ray Bias set, you shouldn’t have any flickering. With the Standard materials converted to VRayMtl, you should be rendering quickly. And with the textures set not to blur, they should come out nice and crisp.