Hi, I always find problems exporting from blender to sculptris, and I know that sometimes is not only because of the non manifold issues. The main problem comes from too many triangles sharing the same vertex.
The question is, is there any way that I can select this kind of vertices so I can identify them in a complex high-poly geometry, and then fix them?
Maybe any addon for selecting vertices by the number of sharing edges, or similar?
Try this. In blender go into sculpting mode. Select the inflate brush and set strength to 0. Under Topology turn on dynamic topology and check the collapse short edges option. Now brush around the problem area and it should even things out without changing the shape.
Yes thank you I know that, but it works only in the case you know where the problem is located.
But in a high poly model you sometimes don’t know where it is.
Using decimate modifier may work aswell, but at the cost of removing some of the detail of the model.
The way is to get a selection of these problematic vertices.
But how? that’s the question…
Under select similar in verts selection mode you have the option number of adjacent faces and number of connecting edges with greater than equal or less suboptions I think you should be able to work with that. Face and edge similar selection mode have possible options as well eg in face mode you can select by ‘less area than’ or ‘perimeter’.
Thanks! Actually I tried that but I didn’t realise about the options “equal” “greater”, etc…
The problem is that you need to select something similar first…
So what I have done is create a disc with a vertex connected to 24 edges, join to the object, select the vertex, shift+g for selecting similar, then choosing amount of connecting edges, and choosing the option “Greater” in the tool box.
The problem in sculptris comes when there are greater than 24 edges connected to one point.
A little intrincate solution, but it works! 
Sounds like way too much work for what you want to do, but if it works, great…
The problem is that you need to select something similar first…
Well I was thinking this was not a problem but a solution! What is the problem with visually scanning your mesh and selecting a vertex that is as densely connected as you want and selecting all the vertices that have more connections. Anyway that’s how I use these commands.
In my case it’s a dense mesh sculpted with dynamic topology in blender that I want to continue in sculptris.
So I have a lot of tris and it is quite difficult to find one vertex with more than 24 edges in that mess…
So the best simple way for me is creating a cone of 24 segments. I select the vertex on top of cone and I get the similar required selection that way.
Anyway it shouldn’t be very difficult to create a script for this, having the tool for similar selection integrated. I mean without having to select something similar, just writting the number of connected edges. But unfortunately I have no idea of scripting.
If someone has some and can share it please…