Was wondering if there is a tutorial on making your own grain, in the model, not on a texture.
Thanks!
What do you mean by this? Are you thinking of modeling 3D wood grain?
In Blender, make a plane (shift + a, then select plane). Apply a subdivide modifier (subdivide 10) & a displacement modifier, and a decimate modifier (.03) to reduce the file size from 100+ MB to 5 MB.
https://www.textures.com/download/3dscans0024/126738?q=wood+planks
After applying the modifiers, you can export the .dae to SketchUp.
There might be a 3D displacement plugin for SketchUp too.
P.S. Usually a texture and bump map is enough to get a realistic effect, but you can do it however you want. This way is harder, but it definitely gets cool results.