Hey guys – do any of you do sculpting of mechanical models? Scultping is great for organic stuff, but seems weak for mechanical stuff where straight edges, flat planes, corners and the like are required. Zbruxh has a set of tools for hard surface modeling – do you guys know any tips or tools for this kind of thing in Blender?
I think Blender doesn’t have any hard surface sculpting tools because it doesn’t need any. Just use subsurf. If only part of your mesh requires sculpting remember that multires behaves just like subsurf until you actually start sculpting, so you can model it and then leave the ‘clean’ sections untouched. Or you can always put your models together from multiple objects. I can’t really imagine a situation where it would be better to use sculpting for hard surface work when you have subsurf. Although I do often use multires to make larger nicks, dents and general damage in my hard surface models.
Well, I was thinking more like making small indents for plating, holes for screwholes, cris cross lines for grating, etc, so that then you can bake it to a normal map. You can model these things, but the topology gets so messy. and subsurf modeling of details can get awkward (say,modelling a screw hole, the edge loops needed to place the hole will cause an edge crease elswhere, whilst you wanted a nice flowing curve)
If you want to make a normal map you don’t have to sculpt to do so. You can make those ‘mechanical’ objects by normal poly/subsurf/high poly modelling and bake that to a normal map.
Yup. You can actually model your screw hole for example by duplicating a face, raising it from the surface a little and modelling there. In the end a normal map stores direction only, so it doesn’t matter if it’s raised. The trouble starts when you want to bake a displacement map too.
Here’s a screenshot to better show what I mean.
I have heard that term before – is a displacement map just a bump map?
Yes and no. They are essentially the same thing in that both store relative heights. However, people usually refer to hand-made high-frequency maps as bump maps, while displacement maps are usually baked from high poly versions or otherwise generated. Some people use the terms interchangeably.
Others will insist it’s about how you use them - with bump maps being height maps used with a shader and displacement maps being used to actually alter the positions of vertices in the mesh (you can do that with the Displace modifier in Blender).
do you apply it the same way - as an image texture with it set to influence the normal or do you set it to the displacement modifier?
Like I said, you can do it either way, depending on your situation.
You changed that last paragraph after I posted, just to make me look like a dumbass, didn’t you? 
Oh, sorry. I always just edit my posts if something new comes to mind within a minute or two of posting. 