To Bevel or Not to Bevel!

Quasar

I'm rebuilding a part of a timberwolf model I made a while back, and when I try to make the armor plating on the round center torso, I get mixed results. What I'm doing is cutting then beveling/extruding the faces outward using the "local normal" setting so that I get an even thickness everywhere. As you can see in this picture, I get good results with some nice smooth edges. However, in more complex areas where my cuts intersect a lot of polygons, I get some distortion in the edges after beveling and it's very hard to manually correct. So my question is, can I create plating like this so that I always get smooth edges and the thickness remains constant with another technique? (I'm using max 6}

Thanks

Eric Chadwick

Looks like maybe you're not using subdivision-surface modeling techniques? We're using it here for really nice smooth high-res mechanical models. Takes a bit extra work for some areas, but you can get very nice bevels out of it. Basically we just model with edge loops, and see how the subdivision performs, adding/moving loops where needed. Modeling with Edges instead of Faces. Sorry I don't have a nice picture to share.

Quasar

Not sure what you mean exactly Eric, but this is what my wireframe looks like



I think the distortions are happening where there are triangles.

Eric Chadwick

Hmmm, now I see. Unfortunately, the kind of modeling you have there creates all kinds of problems. It will be easier to get smooth bevels by re-creating the model from scratch, using edge-loop modeling and subdivision surfaces. If you're working in 3ds max, and it looks like you might be, look up NURMS in the help.

Here's a model that was made here for normal mapping.
The high-res subdivided model...


...and the low-res "cage" model, with the subdivision turned off...


Now, this model isn't as "clean" topologically as it could be, notice the triangles on top of the cylinders, those create dents in the high-res model. But for our purposes this was fine since the model was converted down to normal maps and this kind of shading didn't really show up.

Here are some links that might help you understand the technique.

Subdivision modeling resource page
http://maxrovat.sns.hu/subdiv/

Bay Raitt's modeling notes
http://cube.phlatt.net/home/spiraloid/tutorial/modeling.html

Subdivision Surfaces in XSI
http://www.iro.umontreal.ca/~roys/softimage_xsi/files/docs/html/model/subdivs.htm

Does this make sense? I hope it helps.

hawken

not to take this off topic but EricChadwick, how did you go about texturing this? obviously uv mapping the lot would be a pain in ass, so is there some sort of automated bake-to-texture with auto UVW mapping in max?

Eric Chadwick

That's the cage for the high-res subdiv mesh, not the low-res in-game model, which is much simpler.

James, the guy who built this, says he uses UVW Unwrap to planar-map selected chunks of the model, or UVW Map to cylinder-map other chunks then collapse the stack, then UVW Unwrap again to arrange the pieces. Also Deep UV to relax the UVs, works much faster/better than that UVHelp script.

Eric Chadwick

Here's the in-game model (it's meant to be seen much smaller on screen BTW).


(thanks again Martinez for the polycounter, that thing's great)

Quasar

Yeah I know how to do that type of modeling Eric, but it doesnt work for my model because it's not accurate for what I'm trying to achieve.

The point I'm trying to make in this thread is that after extruding a large number of faces inwards/outwards along the normals, I get distorted edges, mainly around the windows. I also don't want to round the edges, what I meant was edges with a smooth curvature and sharp edge when I originally said "smooth edges". Although I can probably get away with the distortion as it's not too noticeable when rendered from a small distance:

Eric Chadwick

Well, with that grid-like tesselation you have, you're running into problems whenever you try to cut across the grid, since then you're fighting it.

You can create very hard-edged bevels with subdivision, just by placing two edges really close together. You do get a lot of control, it doesn't have to be smooth and blobby.

Quasar

I see what you're saying, I've made a few models like that, but in this case I have to cut into the grid so that I can keep the curvature of the base object. If I do the sub-d technique I'm afraid of getting small variations in the surface from manually editing the verticies/faces. Sub division works well for the model in the pictures you posted because it's made up of many elements, where as my model is a continuous, and for the most part, smooth mesh. One thing I have tried though is making a cut very close to the the edge of the faces I will extrude, this gets rid of all the triangles, unfortunately, it doesn't seem to get rid of those small distortions I suppose I can give sub division a try, I don't know how well I can maintain the shape though as it's quite tricky to get

Eric Chadwick

Sub-D does take some getting used to, but it can create a shape like that cockpit. I know that it might be a bummer though to start over when you've come so far.

But it's only the end results that count, whatever way you use to get there doesn't matter if it renders well, right?

I know from experience that trying to adjust an already-tesselated mesh can be very frustrating. You can run into performance problems too... in the viewport, in the UV editing, in the rendering. Sub-D helps you avoid a lot of that, but it has issues of its own too.

You might try only extruding along the existing grid lines, not cutting new ones, and just sliding the edges around to get closer to the shape you want. Try the Constraints: Edge/Face tools in Editable Poly, might help.