Surfacing logic

[Anonymous]

Hi, I've been trying to figure out the surfacing logic of this car from the FiveAxis article and am having a very hard time figuring out the whys. I'm hoping you all could help.
There are countless surfaces on this car. If you take a look at the top right corner just before the cut line on the hood, you'll see 3 tiny little surfaces.. That's just one of many examples on this car. Why would you need so many surfaces? the car shape seems to be simple enough to not need all that. From the past threads posted here, I gather that this might have something to do with other surfacing software that has trouble reading trimmed surfaces. Is that the reason there are sooooo many smaller 4 sided surfaces with minimal trimming?

http://aliasdesign.autodesk.com/files/21801_21900/21807/file_21807.jpg Edited by: AngryJohn32 on Nov 7, 2008 6:23 PM

[tekbot]

1st of all. Great observation.
its awesome that you knew that you should be questioning it. I know these guys so i asked em whats up with those.

its confirmed that the areas that have all the small patches is either production data or modified production data. Being Toyota, I would assume that those were originally created in Catia.

the obviously modified areas of the car such as the bumpers are clean and fairly simple patch layouts. Alias rocks this type of modeling superbly. now that Alias supports Bezier surfaces (single span surfaces) you might see some areas that may look like they have several smaller patches, but when done correctly, its totally cool.

Keep surfin'

[Anonymous]

Thanks a bunch, Tekbot. That definitely makes things less intimidating.

[design22]

It wasn't so much the little surfaces that I noticed, but the large surfaces seem to have too many isoparms to be considered class A. Right? At least that's the impression that I got from "listening" to Elenor, Euwe (?), et al. Guess I'm still confused about that.

[mratliff]

My guess is that the original data was in the form of polygonal mesh data.
This data was probably run through an auto-fitting algorithm that split up the surface patches to assure a precise fit.
-Matt
Autodesk Product Support Specialist

[dangertaz1]

If one span is good, then 500 must be better!