Hi Oskar, well ZBrush is much more completely focused on that kind of a thing, I'm not personally familiar with Modo's sculpting tools so I can't give you a very good answer myself but I don't recall hearing very much about sculpting being a particularly big area of focus in Modo.


> I will get a dense mesh or I will need a clean UV to apply the
> generated displacement to?

Well, if you're having difficulty with UVing, then you would probably want to make a dense mesh and then save the altered geometry rather than doing it by texturing.

If you are able to get good UVs, then it sounds like you can already use Modo to do what you need, is that correct?


> And should i be terrified about loosing the vertex
> normals in modo?

Well, it depends on what you are trying to do. Since you are trying to actually add imperfections it may not be so important for you to get the super accurate smoothness of the original vertex normals.

If you want things to look completely perfectly smooth and pristine, that could be more of a factor. But it seems like you are actually trying to avoid that kind of a look.


You might try 3D-Coat first, it could possibly be easier to get into initially than ZBrush.

- Michael

Hi Michael!

I guess Zbrush is the king when it comes to sculpting, but modo has a toolset that allows you to sculpt both real geometry and displacement maps. One big difference is that modo can't push as many polys as Zbrush. But for my needs it seems that i can get by with modo. Altough it does bother me that i have to delete the vertex normals :) At least if I go with the dense mesh workflow.

But wouldn't I loose the vertex normals in any app when I start to modify the mesh?

/Oskar

Hi Oskar,

> But wouldn't I loose the vertex normals in any app
> when I start to modify the mesh?

Yes, you will - the vertex normals are tied to the particular shape so once you modify the shape you also need to have new vertex normals to go along with the new shape.

But like I mentioned, the original vertex normals are more useful if you want a super smooth and non-perturbed shading that looks exactly like the original NURBS model, which tends to be what people are usually more focused on with "hard surface" type mechanical models.

You seem to be talking about making bumps and imperfections on your shapes, so maintaining super smooth precision shading and uniform reflections does not seem like it would be as much of a priority for you.

Just as a general tip, if you do need to work on output generated from MoI without preserving vertex normals, it tends to help if you generate a more evenly diced up mesh instead of having a mix of large polygons (from stuff like planes) right next to small polygons for more curved areas. Meshes that are made up of more evenly sized polygons tend to work better when they are edited and have new vertex normals created just based off of the polygons.

- Michael

Well, my most important reason for using Moi is that it is fast and easy for hard surface modelling. I guess I have to choose between super smooth and extra details from time to time.

Anyway, I feel alot more comfortable deleting those vertex normals now.

And thank you for the tip!

/Oskar

>Did you apply the displacement to a fillet?<

Yes, and applied a red style in Moi where I wanted to use the weld material/displacement in Modo.

Hi Oskar,

> I guess I have to choose between super smooth and
> extra details from time to time.

Yeah, sometimes you will need to make this choice.

But if you can keep the geometry in place (with vertex normals), and only paint a displacement texture map on it to add detail, that's the case that gives you the best of both worlds.

Can you maybe describe a bit more about why you were unable to do that with your original case? Does Modo have a problem dealing with UV seams making it hard to make a good looking displacement in an area where there are seams?

Maybe in the future Modo could use the Ptex system to make that work better - it's a system that can be used instead of UV mapping, it instead makes a kind of separate mini texture for every little individual polygon but then also has a filtering mechanism that is supposed to make things work better across borders.

I think Ptex was particularly designed to make painting on stuff easier without having to set up UV mapping.

- Michael

Hi Michael,

I agree that a displacement map is the best compromise. Modo is pretty good with UVs so that is not the issue. Although I'm no expert on displacement maps, I think they are very sensitive to UV-seams. In this particular case with two cylinders I think it is very hard to get a good UV without seams. To make things even worse there is no fillet between my cylinders. If I manage to add fillets I think it is going to be ok.

If Ptex gets widely adopted it is gonna make life alot easier for alot of people, me included.

Thanks for your help!

/Oskar

Hi Oskar,

> Although I'm no expert on displacement maps, I think they
> are very sensitive to UV-seams.

I'm not sure if that absolutely has to be the case though...

The Ptex stuff for example basically has the equivalent of seams at every polygon edge, but apparently it also incorporates some mechanisms to make the transitions work better.

So I'd think it would be possible to have something similar applied to regular UV map displacement painting.

You may want to try ZBrush or 3D-Coat to see if they handle doing displacement map painting across regular UV seams better than what you are seeing in Modo.

- Michael

Hi Oskar, I did a bit of digging, and there appears to be plenty of complaints about displacement map painting in Modo not really working as well as it should across seams, here is a discussion thread:

http://forums.luxology.com/discussion/topic.aspx?id=37566


So based on that discussion, I would say you should definitely try 3D-Coat at least and see if you can paint a displacement map better in there, and then just assign that map in Modo instead of doing the actual painting in Modo for displacements.

If that eliminates the issue you ran into with seam displacement artifacts, then you would have a workable general solution set up.


All kinds of models can have UV seams in them, so I don't think just trying to avoid seams is really feasible.

- Michael

3D Coat has Ptex now.
Brian