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View Full Version : Rebuild Curves HELP!!

modeling-man
09-03-2003, 07:16 AM
Ok so I'm frustrated....very frustrated. I've searched and read and searched some more on how to get rebuild curves to work. I understand that to use the bi-rail tool I need to make sure that the curves spans (eps) are the same so that the intersections match up. However, when I select my line go to "rebuild curves" and try to use one of the options to rebuild the curve, it doesn't work...I went to the help tab and got some great explanations all of which did no good. I guess I just don't understand what I need to do specifically to lessen or gain more spans....I wish I could just type in the friggin number...like:

"hey Maya, I need 6 spans total...think you could do that? thanks"
instead I get:
tolerance = 233.21 Keep Original?

This project was supposed to be end of Sept. but got moved up to the 12th...so ya I'm freaking out. Its just a simple model of a Porsche and an Indy car...I'm just trying to use splines since I heard they were a great way to model a car. Max's splines are a serious pain seeing as they like to move all over the place so I chose Maya. However, in the tutorial I'm using (Subaru Tutorial) I'm stuck just on the second usage of Bi-rail...I'm pretty sure once I can figure out this curve issue I should be good to go. I got the bonnet to work but all the rest require this elusive "rebuild curves" step which is just driving me batty. A nice slo-mo step-by-step process would help a bunch. Here's the link to the start of my model. The front view from the blueprints I found actually don't match up for some reason and when I imported them into Maya they imported enlarged?! No biggie the main prob is the rebuilding curves.

Porsche File (http://www.subshape.com/porsche_gt3r.mb)
Porsche Side Reference (http://www.subshape.com/side_gt3.jpg)
Porsche Front Reference (http://www.subshape.com/front_gt3.jpg)
Porsche Top Reference (http://www.subshape.com/top_gt3.jpg)
Porsche Back Reference (http://www.subshape.com/back_gt3.jpg)


If you think this is just not gonna happen perhaps some of you could point me in the direction of a good tutorial for modeling a car with just Polys? I got some saved but typically they start with splines of some sort.
Any help would be very much appreciated.
B
dmcgrath
09-03-2003, 07:45 AM
The option box for rebuild curves is where you need to sit and experiment. If you are reducing the # of CV's make sure that the curve can be handeled down to that #. You should make the curve degree to 3 (Cubic) and then it should reduce or increase on the rebuild easily.
stallion151
09-03-2003, 07:50 AM
just checked your scene. nothing wrong there.

with curves all your information relating to rebuilding is in your Attribute Editor.
If you select your curve go to the AE then look for nurbs curve history...the very first rollout.
There will be a U and V spans. You have to match those to get a nice bi-rail/loft/etc.

If you birail 2 curves with eg 0 10 and 0 9 maya will do some crazy looking inter-calculating action, don't know what, but you'll get a lot more isoparms than what you wanted. Select the curve with 10 and delete one cv or insert a knot into the other.
To get even rebuilding first rebuild to how many knots you want then rebuild again with the CV's checkbox ticked. This will re-parameterise it.

Use 0 - #spans, so thats basically what i do, just keep an eye on that box in the attribute editor. It will bring you glory and fame.
modeling-man
09-04-2003, 05:53 AM
Ok so I tried what you said...seriously I just don't get this. I even follow those "help" things at the bottom of the screen. Why the hell can't I just add a friggin point in the curve where I want? Why does it always start where it left off? I tried "insert knot", the first time I tried it, it prompted me to select a "curve point" so I did...then chose insert knot...I did this twice in differing spots. Then assuming it worked <eventhough the spans under the attribute editor showed no different> I "rebuild curve"........nothing.

WHY is this so Q#&$$ frustrating?! I've started a model in Max since I know that program better..and since this is on such a ridiculous time schedule...I'm using polys as well no splines since Max splines are crap IMO.
Anyways I'd hate to just quit on this since I WILL have to learn it sooner than later so please if someone can give me detailed help...as to what exactly I need to do to get this damn curved to match up.
Thanks again for the previous help I just think I'm too stupid to figure this out right now and need my hand held...annoying I know but I'd truly appreciate it.
sethmisek
09-04-2003, 08:59 AM
Im not big on spline modelling but
I think you right click on the curve and select edit points. Select two of the x shaped edit points. Select the insert knot options and use between selections.
Or select curve point and click on the curve it will add a yellow dot on the curve. Then hit insert knot
Or select the curve and go to the rebuild options. press reset options and pick the number of spans you want and the degree that should be all you need to do.
stallion151
09-05-2003, 07:25 AM
yeh like sethmisek said, just click and make a curve point and insert knot...in the options you can choose at curve point. Use that.

Also when you insert a knot, it automatically equals out the curve spans. The knot should be where you put it, if you check the edit points.

When you rebuild curves and the cv's don't seem to match, use 0#spans, then check NumSpans, this will rebuild it without changing the span amount, or the curvature of the spline, but space out the cv's equally.

Also don't forget the rebuild types, try those if your still in a bind...if all else fails....come back here.
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