> Is there a way to prevent the ribbing from happening, but perhaps more important is the
> question if this "ribbed" model is of lower quality than the original MoI model, or if it just
> "a visual thing". It's important for me to know in relation to 3D printing, as I would have
> to think carefully about what I'd create in ZBrush and what I'd create in MoI.
If I remember right I think the ribbing effect is a visual thing that ZBrush does - it's displaying the mesh in a faceted style so you can more easily see individual polygons while working in ZBrush. Look for a display setting to show meshes using smooth shading rather than faceted shading.
> When I try to increase the number of polygons by subdividing the model in ZBrush, it screws
> up the model and becomes unworkable (see attachment).
That's because the option to do subdivision smoothing was enabled. The output from MoI is not set up to do sub-d smoothing, so you would need to disable sub-d smoothing style subdivision and use just plain polygon subdivision. I forget exactly what it is called, it's something like "Subd" or "smooth" option for subdividing.
> Regarding the meshing options when exporting my model as an OBJ: am I correct in saying that ticking "weld vertices
> along edges" and putting a low value in the "angle" and "divide larger than" fields will give me the best result?
That will generate denser polygons so if you are planning on modifying things in ZBrush by applying displacement that would be helpful for that.
> Also, am I correct in saying that a value of 1 in both these fields is the lowest value that MoI will
> process? I tried putting in lower values but it doesn't seem to make a difference.
A value of 1 in the angle field is the lowest it will go for that one - putting in 1 there means that any polygon that has more than a 1 degree angle between surface normals at its vertices will get further subdivided. The "Divide larger than" takes a distance value and it can be smaller than 1 unit in size, when you put in a value for "Divide larger than", any polygons more than that distance across will get further subdivided.
> I also realized I can't create something in ZBrush and then open it in MoI. Someone told me that in
> MoI v4 this might be an option, is that correct?
MoI v4 does have a new import method for sub-d meshes, so if your mesh is set up to do sub-d smoothing then that can be brought into Moi v4. But if it is just a simple triangle mesh that will not import back into MoI.
There are different styles of polygon modeling - sub-d polygon modeling and "regular" polygons. Just because you have polygons does not mean they are set up to do sub-d smoothing, a mesh that has been set up to do sub-d smoothing needs to be all or nearly all quads. There is an overview of sub-d style polygon modeling here:
https://www.youtube.com/watch?v=ckOTl2GcS-E
Hope this helps!
- Michael