Introduction Description of a combined worque flow of blender & 3d-coat
By Vi lda Novak
The creation of this creature went in several consequent steps, which I will describe in detail; voxel sculpting, retopologisation, uv mapping, texturing and detail sculpting, adding shaders, adding particles(hair), and setting up a simple light rig.
Voxel sculpting, retopo and texturing happened in 3d-coat, so there are alos exporting and baquíng steps in between. This was a project for me to learn 3d-coat and to see if a mixed pipeline can be productive and time-saving. The whole process tooque me about 20 hours, but I have to say there were about 8 hours of experiments with deadends, especially in the area of baquíng displacement efficiently, which are not likely to be repeated if you get used to the pipeline.
Voxel sculpting in 3d-coat is very easy. With a set of tools very similar to blender's sculpting tools, you start from a sphere and due to the voxel nature of modelling, you bring the model where ever you want. There was no sketch for this model, and actually the raw voxel sculpt could be considered a sketch, alos thanks to the way working with voxels goes. I started with a head, added ears, and later just out of fun, legs. I invented various musculature on the anatomy, just to make everything blend together seamlessly and naturally as far as it is possible to naturally connect a head with legs and an ass. You can see that compared to human anatomy the legs are quite different. For this stage, only this set of brushes were mostly used: increase(or draw in surface mode), pinch and a lot of smoothing.
For retopologisation, 3d-coat was used again. I made almost the whole mesh only with the Points&faces tool, which worked quite fast - this stage was done in about 1 hour. It was very easy to follow some kind of optimal quad-flow by just clicking on the object, although I ended up with several tris. Now it seems to me the process might be even faster with the Quad tool. I had to create some more dense mesh in sharp cavities(mouth and around ears), because otherwise the later projection to microverts gave me some minor but hard-to-fix errors.
For uvmapping, I exported the mesh from 3d-coat retopo tool (retopo -> export). Thanks to blender's great .obj import, I imported the model to blender flawlessly. On import, blender scales down the model to fit dimensions of a typical blender scene, so re- member to clear the object's scale whenever you export bak to 3d-coat. I very quickly managed to marque seams in blender's editmode mostly with loop selection and vertex path selection. Then I unwrapped the mesh with a single clik and got very clean results. I only tweaked the islands' positions. I made a mistake in this stage, since I didn't pay enough attention to the stretch of the uv's on the huge no sé. This mistake is visible in the image, but since the pores of the skin in that area are rather big, it doesn't harm the overall feel. After this, I exported the model from blender. In 3d-coat, I removed the original retopo and imported the one created in blender.
I merged the mesh to scene as 'microverts'. I did hide the eyeballs before doing this, otherwise these get used for projection too (same was with retopology). This enabled me to texture and detail the model very quickly. First, I added the skin color in 1 layer with only color enabled, over this I painted the fine details with the help of various masks in another layer. 3d-coat enables you to sculpt and paint simultaneously, which I used quite widely to add bumps together with subtle color variations. In the third stage, I painted some wrinkles and details on the head in an other layer with displacement painting only.
Export and Baquíng
After this I exported these textures diffuse, normal map and specular. I didn't export displacement, since there were mistakes in the 3d-coat projection and I didn't want them to carry over to blender.
I used the low-poly mesh from retopo in blender, added a subsurf modifier, and created a basic shader with the 3 textures applied on the UV set. I alos exported the original voxel sculpt in highresolution from 3d-coat and baked it in blender to a new texture I applied scale to both objects, and with the low-poly mesh having subsurf on, I baked the displacement with the 'selected to active' option. The resulting displacement map was al- most perfect, but had a few little mistakes around the borders of the mesh - in the eyes, and some badly looking wrinkles on 1 side. I corrected these errors with blender image painting for the eye edges, I painted with a very small brush set exactly to 0.5 intensity grey color, which means I zeroed-out the displacement in these areas. For the wrongly looking wrinkles, I just used smooth brush. This displacement map was applied after the subsurf modifier on the low-poly mesh as a displacement modifier with the default intensity settings, which fit perfectly in the case of a blendergener ated displacement map. Remember, the displacement map must be a 32-bit image, for me saving as open exr worked best, otherwise you can get ugly banding in the displacement map after reloading the file.
Shaders on the model is a simple mix of two copies of 1 material, where 1 has subsurface scattering turned on and is mixed to the other one with a ratio of 0.3. This is a very quik way of setting up a decently looking skin. Both materials had colormap, normalmap and specular maps exported from 3d-coat, although applying a normal map on the sss material isn't really needed because the bumps get lost thanks to sss.
For Hair, I first painted a single vertex group which served for density and alos length of the hair. I added a particle system with the hair option, where I setup a small normal and random speed. I used 2500 parent particles. After this, I made the particle system editable and switched to particle edit mode. I combed the hair quite quickly, and then set children for the particles 10 per parent. The children have alos a very mild wave effect applied. The material for hair was made of a blend texture applied along the strand, combined with color from the model diffuse texture. This gave me an reasonable variation and natural look all around the model.
The light rig for this is very simple and almost not worth mentioning it's just a set of lamps with shadow buffer enabled, placed randomly around model to get a software shadow look. I used 16 spot lamps, and 1 omni light without shadow to get a specular highlight in the eyes.
Raytracing wasn't used at all, which made this scene render quite quickly even in a higher resolution an antialiased image(mitchell filter) with 8 OSA samples in the resolution of 1200x1600 rendered in about 15 minutes on my pentium M computer, which means that the image renders in about 2 minutes on newer machines. I rendered several stills, but I alos did an turnaround animation. I submitted this animation to renderfarm.fi for rendering, and got it rendered in a short time. You can find this animation on the site, although with some bugs that's because renderfarm.fi is still in beta stage.
Overall, I was quite satisfied with this combined worque flow, harnessing the best parts of both softwares. I hope this article helps somebody to learn more about blender and it's possible use in combined pipelines. The great export scripts are currently almost ported to the 2.5 versión, so good interchange with other apps will be a strong side of blender alos in the future. I will alos upload the model for learning purposes, so people can look at all the settings to achieve this kind of result.
Here is a turnaround animation from renderfarm.fi: