Slightly off topic: Nurbs

[cakewalkr7]

Hi everyone. It's been a while since I've posted around here but I've run into a problem in max and no one on the other max boards have been able to help. So, although it's not necessarily arch viz related, I was hoping someone here might be able to help.

 

I got a free month subscription to Lynda.com and thought I’d look at some of the max lessons there. One of the chapters dealt with nurbs modeling a car. Poly modeling a car has taken me a long time so I thought I’d give it a go. Everything was going along great until I got to the part where I needed to use the door curve and project it against the side panel surface and then trim it to create the door. I followed what the video was doing but I can’t get it to trim. I reset max and tried a very simple surface and projected curve trim and it worked fine so I’m lost as to why it won’t work in this file. Are there any gotchas I should be aware of to make trimming work as expected?

 

One thing that I am noticing is that in the video (and in other simple tests I’m running), when I use the "Create Vector Projected Curve" option, after I click the curve the surface turns blue when I mouse over it. In the car I’m modeling, the side panel surface does not turn blue. But, if I click it anyway the curve appears to project correctly against it… it just won’t let me trim it. Thanks.

[DavidR]

I know you've heard it, but Max nurbs suck, and Autodesk hasn't added anything to them since Max3. I've tried Maya tuts on Max, and run into problems where Max won't trim across an edge. Example: make a nurbs sphere and try to trim across the pole/top -you can't. Even nurbs spheres are created by deforming a 4-sided surface, and Max has limits when trimming across bounding edges (Maya doesn't seem to have this limitation). Your car door may be 'violating' a similar nurbs rule. I knew nothing but nurbs for my 1st 5-6 years since I come from a Cad background, but I've dumped nurbs (in Max) in favor of polys due to the flexibility, ability to add local detail (unlike nurbs), seamless models regardless of complexity, etc. I still love nurbs, just not Max's, and unless you have a specific need, I'd say forget the nurbs tut, and do something that won't leave you with a great bloody bruise on your forehead.

[cakewalkr7]

Thanks David. That's what I'm finding out the more I struggle with it that Max's implementation of nurbs just isn't very good. I will probably keep going with the poly modeling but I was interested to see just how much more quickly I could model a car with nurbs. Oh well. Thanks.

[DavidR]

It's a good thing to know how nurbs work anyway, so that you can work with data from other sources, such as iges output from cad programs; you frequently get untrimmed surfaces, flipped normals, etc, and it's good to know how to repair them, where possible. Also, about once a year, I find myself doing something in Max nurbs because it works better than poly for that one thing, so I'm glad it's there, such as it is. Maybe Autodesk will dump Max nurbs and paste Maya nurbs into Max? -that would be freeking awesome!

[Jennifer]

Hi!

 

I agree on the assesment on NURBS. It definitely needs a serious upgrade, and they either need to port over some of the Maya functionality, or look into getting more of the http://www.npowersoftware.com tools like PowerNURBS.

 

Rhino seems to be the tool of choice for NURBS modeling outside of max, but getting clean geometry into max can be an issue. The nPower Power Translator will let you bring in Rhino models as NURBS, along with a number of other formats. Another thing that needs some serious updating in max are the translators, and the Power Translator does a great job. I used it for IGES files from my solid modeler, and it worked great whereas the standard max IGES didn't work for that flavor IGES.

 

Enjoy!