This week, we learned a bit more about Mudbox, mainly how you can "convert" your sculpt, which has a lot of detail (and polygons) to a low-poly asset. This time we worked on rocks.
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| The result with my method - 990 tris Left: no normal map (wireframe) Right: with normal map |
- Start with a standard cube in Mudbox, sculpt it like a rock mainly using the grab- and scrape-tools. Apply surface detail with the foam-brush.
- Export as an .obj-file and import in 3ds Max.
- Use the ProOptimizer-modifier (about 5-10%) on the imported model to reduce the amount of polygons to a more manageable level. The resulting model will be the one which will be baked.
- Make a copy of this high-poly model and use the ProOptimizer tool again to make a low-poly version. This will be the model you want to put in-game.
- To unwrap the model, export as .obj again, import in RoadKill, select along what edges you want to unwrap the model, export the result as an .obj and re-import it in 3ds Max.
- Tweak the UV's so they are more optimal.
- Bake the high-poly on the low-poly (with the Projection-modifier) and ta-da: a normal map!
- For the diffuse: just put a realistic stone texture on it, and (using the normal map as a reference) trace the edges of the stone with a white brush, to emphasize the shape of the stone.
That is quite a lot to swallow, and what is especially annoying is the fact that there are some problems with this workflow:
- When optimizing the original mesh from Mudbox with the ProOptimizer, this creates artifacts that have to be painted out manually in the normal map, which is quite time-consuming.
- You have to tweak the low-poly mesh and the cage of the projection-modifier to properly bake.
- The diffuse texture has seams.
- No connection between the normal an diffuse maps.
So I did a little bit of research, and this is my modified workflow:
- Start with a cube in Mudbox and sculpt the shape of the rock. No surface details yet! (But make sure the shape is already well-defined)
- File -> Send to 3ds Max (thanks to this shortcut, you don't have to export and import, however, it took some time to do this, so maybe I'll just stick to the .obj export-import)
- Use the ProOptimizer, but this time, immediately for the low-poly mesh.
- Export for RoadKill, make your UV's, re-import and optimize them in 3ds Max... (same as above)
- Send it back to Mudbox.
- Now, I played around a bit: I did a little basic diffuse texturing in Mudbox, then sculpted in (surface) details and textured a bit according to those details. (For example: scratches in the texture => scratches in the normal)
- I also tried the technique from the video I discovered last time, where you use your diffuse as a displacement map. It was not very clear from the video, but first you have to export your diffuse texture by right-clicking on any paint layer of the diffuse-channel and choose "Export channel to PSD..." I converted it to black-and-white and put more contrast in it. Then you can go to Maps -> Sculpt using Map -> New operation... and just choose your image and the model, and it adds it as a new sculpting layer, so make sure you are at a high subdivision level.
Here is the video again: - For the normal map: there seems to be this cool feature to just export your maps. I only tried for the normal map, but apparently it can also generate ambient occlusion. You can find it at Maps -> Extract Texture Maps -> New Operation... and check Normal Map, select your texture size and name. I set the compatibility to 3ds max, but left all the other settings unchanged.
- Apply the normal map to your low-poly model and check out the result!
This is quite a lot of text, maybe I should make it in a video once... Or find a nice workflow tutorial.
If you know any good ones, again, feel free to leave a comment!
Next week I'll probably learn more, so the workflow may be tweaked further. For now, I'll work on our assignment, and I'll let you know what I discover. :)
Until next time!
Greets,
Marcia
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