View Full Version : Basic topology questions

 Kenage02 February 2007, 09:04 PMHi all (: I'm just starting to model Intermidiate- sort of models, and since I'm lacking in theoretical and practicle knowledge about topology, tesselation, edge loops and flow I thought it might be a good idea to seek it around here! So basically, I want to learn how to create correct topology for that will smooth the way I want it to with the right flow of edges (I read that this is most important for deformations for animation purposes). I also want to learn the logic and theory behind all that. I guess that most of my practical knowledge will be gained through trial and error, so I'll be more than happy if you could point out some good tutorials and articles on the subject and of course any comments, tips and the likes from experienced ppl. Thanks ahead!
GreenShellFactor
02 February 2007, 12:35 AM
Well, there is no formula for good topology. The best way to learn how to model is to model. You start to see models differently the more you do and the more wireframes you look at. But here are a few pointers to keep in mind:

Ideally, you want to maintain quads. This will allow for predictable smoothing and uniform deformations. While triangles are okay, they are more used for low-rez / game stuff. N-gons, or polygons with more than four sides are a serious no no - renderers hate them.

Seems you know that edge loops should form somewhat concentric loops around the model - think of rubber bands wrapped around the model and pinned to the surface. When loops meet, they usually form what is called an extraordinary point - a vert with more than 4 connected edges. These are okay as long as their placement is in an area where deformation is minimal. Think about it, it's a single point controlling a whole lot of geometry.

Also, familiarize yourself with the different surface generation techniques. It's a lot easier to create surfaces that can be cut down than to model poly by poly.

Hopefully, that'll start you on the path. Let me know if you have any questions about what I said. Take care, and start modeling!

~green

Kenage
02 February 2007, 07:58 PM

I know about the Quads thingy, it seems like the hot topic everywhere... I hadn't thought about the loops that way though, thanks for bringing that up!
And what do you mean by "cut down"? Like boolean/split polygon?

Well, I guess you have no better guide than experience... But let me try to scrape the bottom of the barrel and ask if you have anymore tips? I'm a Maya user, so if you have any specific tips/tricks for Maya that will be greatly appreciated!

GreenShellFactor
02 February 2007, 10:55 PM
By cutting down surfaces that have more polys than needed, it's easier to see what pieces fit into different places. For example, you could create a lofted surface (keeping in mind to change the output geometry to polys > quads, and use control points for the method) and only needed a portion of the actual polys created. You can then simply delete the unnecessary faces and attatch as needed. This is obviously more helpful when modeling things like props.

I was actually talking to my teacher the other day and he said (as opposed to NURBs mdoeling) poly modeling is a lot more intuitive in terms of just diving in and getting your hands dirty, while NURBs uses a more analytical approach.

I would also avoid using booleans - they're buggy when rendering and especially buggy when texturing. There are precautions to take when setting up the geometry to ensure points on each object will line up, but it's almost not worth the time it takes and you won't learn as much as if you modeled the object from the get go. I rarely use them, but it may be a personal preference.

As for residual pieces of advice, start modeling everyday objects. Everything you model will pose different problems/solutions. The thing is all that cerebral data is stored for the next time you model something else. You'll not only be able to know how to fix certain "anomalies," you'll be better able to plan out your geometry in order to completely avoid modeling yourself into a corner.

Personally, when I'm starting a model, I trace curves around the contour of the reference. Which reminds me, ALWAYS USE A REFERENCE. It doesn't have to be set up as image planes, but having photographic reference can in no way hurt your attempt. Even if you make a simple collage in Photoshop, and apply it as a texture to a plane just so you have some sort of map as to what you're actually doing. But getting back to what I was saying about curves, I usually create linear curves just to have some sort of starting point. You can then create and append polys to those curves and can build from there.

Hope that helps a little bit...a little long winded, but you get the idea. Best of luck, and feel free to hit me up with anything you think of.

high five,
~m

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