Blender: Catmull-Clark.

[Chriz Palen]

I suspect the answer is no...but is there a way to partially apply the Catmull-Clark to an object in Blender (i.e. apply it to just where it's required), in order to keep the vertices count lower?   If not; are there alternative ways to smooth selected parts of a mesh whilst leaving the remainder unaffected?

[Drongle McMahon]

Depends exactly what you want to do. The first thing is to do as much as possible using smooth shading (Mesh->Faces->Set smooth) rather than subdivision that will increase the triangle count. This can be applied to selected faces. For finer control, set the whole thing smooth, then use the Mesh->Edhes->Mark sharp and the Edge split modifier to make explicit edges sharp.

Smooth shading will make the faces look smooth, but will not smooth the edges of the silhouette. For that you do have to use subdivision of some sort. You can do a lot selectively by selecting edges and doing Mesh->Edges->Bevel. You can also add edge loops (Mesh->Edges->Loop subdivide) and editing the added loops. It's better for Land Impact to try to limit the subdivision to just those parts necessary to get an acceptable silhouette.

No doubt there are other better ways that others can add. You can separate selected vertices into a different object, apply subsurf or multires, and rejoin, but then you will have a lot of repairs to do. I don't recomend it.

N ote - menu commands here are Blender 2.49 version, later versions may differ.

[Chriz Palen]

 I'm familiar with some of these suggestions and already use them, but I'll have to experiment with some of the others. 

"You can separate selected vertices into a different object, apply subsurf or multires, and rejoin, but then you will have a lot of repairs to do...." 

Yes, I'd thought of trying something like this, but as you say, I suspect it could be tricky.

Thanks for your reply Drongle.

(I'm using Blender 2.62)

[Ashasekayi Ra]

Drongle pointed out some good points.

One other method is using subdivide smooth. If you use it, you can add extra geometry to specific areas. Basically, you select the edge rings in that area and then you use "W -> subdivide smooth". In the latest Blender, you can have access to further options by looking in Toolshelf sidebar (hotkey N). You can increase the number of cuts and adjust the amount of smoothing.

When modeling for games, I usually opt for this method instead of subdivision, or I use the edgesplit workflow.

[Chriz Palen]

"W -> subdivide smooth..."  Helpful information - I really should learn all of Blender's hotkeys.

"edgesplit" This could prove useful for my project.

"When modeling for games"  It's nice to receive some expertise from professionals :smileyhappy:

Thank you Ashasekayi.

[Drago Artful]

I just want to point out a couple of time-saving selection tools for when you're subdividing:

Alt+RMB to select edge loop

and

Ctrl+Alt+RMB to select edge ring.

I just don't want y'all to be wasting your time selecting edges one at a time like I was when starting out 3D modeling... Haha.

[Ashasekayi Ra]

Welcome and good luck

[Chriz Palen]

Yes, useful tips - thanks Drago.