#2
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26th Mar 2007 at 2:39 AM
Last edited by tiggerypum : 26th Mar 2007 at
9:33 AM.
How To Use Smoothing Groups
How To Use Smoothing Groups
I want to start by saying that you don't ever have to worry about this if you follow the standard procedure of not welding and not smoothing anything. However, this is good to know for those times when you do, for one reason or another, need to weld or smooth parts of your mesh.
I don't know if this really qualifies as a tutorial, but actually it's pretty simple.
First, keep in mind what Wes said, the Sims meshes do not have any smoothing group info, so be sure to always save your file as a .ms3d file too, to preserve any smoothing group info that you have added to your mesh.
Also keep in mind that the smoothing groups are not at all connected to the mesh groups - any part of any mesh group can be assigned to any smoothing groups. For example, it would be possible to have a mesh that has only one mesh group, but still make use of all 32 available smoothing groups.
Whenever you import a mesh into MilkShape, the whole thing is automatically assigned to smoothing group 1.
For the most part this would work ok, but there will often be problems where your mesh makes a sharp corner, for example where the hem of a skirt joins up with the underside of the skirt.
In the first pic, I have purposely caused a "normals" problem by welding together the edge of the skirt mesh with the flat "underside" of the skirt. Then I did a "smooth all". You can see the results, lots of darkened areas around trhe skirt hem and the upper legs.
To fix this, I am going to assign the underside of the skirt to another smoothing group. First I select only the faces of the skirt underside - actually, since that would be rather hard to do, I really selected the faces of the entire lower skirt/upper leg area - then I unselected, by vertex, all the faces above and below the skirt underside. Anyway, what I want is to see all the faces of the underside selected, and nothing else.
Next I go to the Groups tab, and in the smoothing groups section I first click the [Assign] button. Then I click the [2] button - this will assign my selected faces to smoothing group 2, leaving the rest assigned to smoothing group 1.
Now, I again use "smooth all" - but look! Now the skirt looks right, no more darkened edges!
That's really all there is to it.
The smoothing groups can be left as-is when you do your final export of your finished mesh, they won't hurt anything at all.
Additional Tips from Wes_H
In the Tools menu for MilkShape is a plugin that comes as a part of the UniMesh set called "Sims2 UniMesh Identify Split Group". This identifies all the "seams" areas on a mesh. To use it, you just run the tool, and it selects all the locations that are unwelded vertice pairs.
The purpose of the tools is not to identify where you should fix the Maxis model, because if you weld these locations, you will have smoothing problems. Instead, what it shows is the locations that Maxis' smoothing groups left unwelded. If you create smoothing groups for the imported model that run on the edges shown, you should be able to smooth all and even use autosmooth and still get properly shaded models.
I attached a screenpic of the female gardener outfit with the Split Group tool selections shown. Note this mesh has clothing and also some object meshing for the tool belt. Using smoothing groups on the tools in the right places will help keep the sharp corners sharp instead of rounded looking.