Streamlining Curves

#1

Hello All-

I’ve been thinking about this article for a while but have never quite known how to approach it- it’s difficult to describe. Anyway, here it goes. Special thanks to all that read this- I know it’s long and I apologize for that. I tried to keep it simple.

CURVES- What a powerful tool in Maya. But I often have a difficult time with them. I am switching from another 3D modeling program called FormZ. Creating curves in FormZ is a piece of cake compared to Maya.

Drawing curves in FormZ is similar to creating curves in Illustrator of Photoshop. Its a point and click process to create 90 degree corners and then being able (without combining, attaching or filleting multiple curves) to create large radii and then into more 90 degree turns. In Maya I do not get that same ability with ease. At least not that I’ve found.

Bare with me for an example-

Draw out the letter “L” with one curve (It’s 2" tall(X dimension) by 1" wide (Z dimension)) . In order to get that nice 90 degree corner I set my EPcurve tool to linear instead of cubic. 3 clicks and I’m done. If I want to create a radius at the corner. I have to set my curve tool to cubic and click in the correct areas to create the curve. No problem, but it’s about an 8 click process. Or I can create two linear curves and fillet them, get an exact radius, trim them and attach them all in one step. Great the less steps the better.

-Problems

1. Filleting two linear curves transforms the linear curves into cubic. I can understand why Maya needs more spans for the actual radiused portion of the curve, but it also adds more spans to the straight parts, which do not need any more spans. I’m trying to keep my spans to a minimum. For my letter “L” example this isn’t too much of a problem. However, some of my curves are complex, I need many sharp 90 degree bends and other parts to be subtle smooth curves. It seems the only way to create curves of this magnitude is to create multiple LINEAR segments and multiple CUBIC segments and then attach them, or fillet them together. This seems time consuming to me and again Maya puts in multiple spans on straight segements of the curve. Another Idea I had was to use a cubic line tool and whenever I need to create a 90 degree turn to put about 3 CV’s in that spot. This creates the sharp bend but I don’t think it is a good idea do to the fact that it doesn’t help with keeping spans to a minimum.

2. I have problems Filleting in multiple dimensions

Draw another line that travels 2" in the “Y” (the 3rd dimension) and place it over the far right part of the horizontal line of our “L” and try to fillet that new line with the previously radiused “L”. I can’t get it to work.

Also- direction seems to play an important part in attaching curves. When I fillet, sometimes I think Maya is secretly changing the curve’s direction. Which makes attaching another curve to it a pain, because one of them needs reversed.

1. Here’s another example. Draw a square with four individual linear lines. I can fillet 3 of the 4 corners, but not the forth. When I try to fillet the 4th corner I get bad geometry and the curve is now periodic. This is largely do to the fact that I have my fillet tool set to trim and join. If you deselect those option you can fillet all 4 corners but then have to go and attach all of them. Somehow, some of the curves are now reversed and I have to re-reverse them…see where I’m going with this?..too many steps.

I’ve done a lot of reading of Maya documents and I feel I understand it’s curves and properties; linear, cubic, spans, open, closed, periodic yada, yada- but I still have problems creating them. I’m trying to keep my curves as simple as possible- yet still keep the detail I need in them. It’s a real challenge for me. In FormZ, you could create a complete complex curve in a fraction of the time I’m creating them in Maya. Am I missing something or are curves just a part of Maya that is time consuming? If anyone has any tips or tuts on creating good clean, low span curves I’d love to hear about it.

Again,
Thanks to all- Any help on curves is greatly appreciated.

-dweinin

#2

hello dwenin, that is a very dense post you submitted there

i believe that you may find some answers to your questions by reading Scott’s Maya Curve Guide which offers an expanded view of what the Maya help files cover.

my apologizes for not writting up a proper response but scott’s guide should explain why you are encountering some of the specific problems you brought up with curves.

/edit: also take into account the differences between the two packages: Form-Z would be the in the same realm as Alias’ Studio package. the precision of curves even differs from between Studio and Maya. with Studio dealing with curves of higher degrees and tools that are much more adapted to hard surface modeling.

Models/Curves created in Studio would be down-converted due to Maya’s lack of support for higher degree curves.

#3

Yeah, it’s dense alright. I’m just glad somebody read it. Posting an article the size of the Titanic doesn’t entice too many readers.

Thanks for the reply. I’ll look into the link you posted. Does Alias’, Studio Tools have the same kind of modeling capabilities as Maya; subdivisions, polys, nurbs and rendering? Those are the main capabilites of the program I’d like to use. I don’t necessarily need, animation, dynamics, fluid and all those other abilities.

-D

#4

given that you do extensive curve work, it would probably be worth your while scripting a curve creation context that allows you to quickly swap between creation methods (degree, EP/CV, arc, fillet) and concatenates these various components of your curve as you go along (and rebuilds as necessary, or does simlpe calculations on arcs to fit in right angles, etc). this will cut out the grunt work that is likely slowing you down. it’ll be a bit of time investment scripting it up, but it sounds like it’d pay off. is there anything preventing you from doing your curve creation sessions in another app?

#5

I could create the curves in illustrator and import them. But with FormZ, I’m use to having great curve control at my finger tips included in the 3D app. Why use two apps when you can do it with one.

And the main reason I don’t create curves in a 2-D program is for that reason alone. It’s 2-D. My curves travel in all 3 dimensions with, fillets and 90 degree angles happening all over the place. Imagine if Dr. Suess was a plumber. Which has been one of my main issues…filleting in 3 different dimensions doens’t seem to work well.

I’ve been reading a bit of the link that mental included. It’s good. I have to read it some more.

#6

sure. id agree. and 2d-3d, well, there ya go.

as an idea of where you might go with scripting up a building context, have a look at a script on highend3d called[size=3]dagMenuProc for MultiDegree Curve v0.9[/size]

it swaps between degree1 and 3 curves during creation and stitches them up when your done, simple, but it should give you some ideas.

#7

I’ll check it out.

Thanks.

#8

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