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 03-12-2013, 02:30 PM #1 dudechester Registered User   Join Date: Dec 2013 Posts: 4 How is it even possible in Maya to simply close a curve/cap a curve? Firstly, I was following a tutorial to catch up on my modelling skills (since im an animator) however, when I got to the point where I make a planar surface to cap the end of this object... It appeared until I wanted to start reshaping it after, hopeing it would simply follow the adjustments, and now I cannot see any planar surfaces there as it turned invisible. I don't like this method, because it's not a flat cap, and it would need a more complicated shape as you can see from the image to close up nicely. I've searched all day online, but there is actually nothing on how to close a nurbs curve into a surface? Im almost certain it should be as straight forwards as selecting a closed curve like in this image, and choosing close curve or create surface from curve??? This step would be very simpe in 3d Max, but how is this done in Maya please? Thankyou. http://s1184.photobucket.com/user/uk...80aef.png.html Last edited by dudechester; 03-12-2013 at 02:36 PM.
03-12-2013, 06:32 PM   #2
ctbram
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Join Date: Jan 2004
Location: Michigan, USA
Posts: 2,997
Quote:
 Im almost certain it should be as straight forwards as selecting a closed curve like in this image, and choosing close curve or create surface from curve???
Ummm NO it's not!

1st when you said created a "cap" did you mean a "planar" surface? If so that is why it disappears. A planar cap is just what its name implies - it's planar. As soon as you move a vert off plan the surface will become invalid.

Quote:
 This step would be very simpe in 3d Max, but how is this done in Maya please?

As far as I know there is NO modeling application, even 3d max where it's as simple as selecting a closed curve and say make a non-planar surface cap! A simple closed curve that is not planar does not have sufficient information to define a surface that encloses it!

Take the image you provided as proof. Start with the non-planar curve now just draw a series of edges vertically from edge to edge left to right and imagine lofting a surface between the edges.

Now take the same starting curve and draw a series of edges this time horizontally from edge to edge top to bottom of the closed curve and loft those.

You will see that you get two completely different surfaces and second you will get a surface that is all messed up because drawing straight edges only creates a proper surface if the closed curve is PLANAR.

You can repeat the exercise drawing straight edges for an infinite number of angles and unless the curve you are filling in is planar the surface created will be a mess. The software has insufficient information to compute the proper contours to cap a non-planar closed curve.
__________________
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Last edited by ctbram; 03-12-2013 at 10:59 PM.

 04-12-2013, 02:10 AM #3 dudechester Registered User   Join Date: Dec 2013 Posts: 4 thanks for the reply. if this is so >> "The software has insufficient information to compute the proper contours to cap a non-planar closed curve." Is there really no right way to close a "non planar nurbs edge hole" like in the picture? The best answer I have found so far is convert it to a polygon mesh and forget about nurbs, but really? There is no real way to close a hole with nurbs? at all?
 04-12-2013, 02:32 AM #4 ctbram Moderator     Join Date: Jan 2004 Location: Michigan, USA Posts: 2,997 My background is in NURBs modeling and Maya's implementation is very weak. NURB's have not been updated in Maya for more then 10 years! However capping a non-planar opening, even in more up to date and sophisticated NURBs modeling apps like Rhino, Inventor, and SolidWorks can be a complicated task. Especially if you want to manipulate the cap dynamically. There are approaches using booleans that could work where you use another surface as a cutter. In Maya after you apply the boolean the cutter is not longer visible but it is still there and with history and can be manipulated. I think I recorded a video a while back on this approach although as I recall it was for polygons and was pretty simple (just to demonstrate the concept). But it should translate to NURBs if you require using them for your project. Maya would not be my first choice for building a full on NURBs model though. I will check to see if I can find a link to the video for you. __________________ "If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675 Last edited by ctbram; 04-12-2013 at 07:18 AM.
 04-12-2013, 12:46 PM #5 dudechester Registered User   Join Date: Dec 2013 Posts: 4 Ok thanks for looking for the video Converted to polygons, it really is much simpler aye... and sure polygons are what I would have worked with in 3d max or any other program too. Nurbs were just intended on a tutorial I was working through to catch up quickly Thanks!
 04-12-2013, 04:24 PM #6 ctbram Moderator     Join Date: Jan 2004 Location: Michigan, USA Posts: 2,997 I cannot find the video. Apparently I never saved it to my yourtube channel. It would help to know exactly what you are trying to do and maybe one of the members can suggest a possible workflow. From the information I have so far I am thinking you might what to create a cap using polygons and then apply a lattice deformer to dynamically change the shape. __________________ "If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675
 06-12-2013, 03:12 PM #7 dudechester Registered User   Join Date: Dec 2013 Posts: 4 Well the conclusion is, that nurbs are best used for making fast modelling, but they aren't as good for practical use as polygons.. So really the best thing you can do with NURBS, is get a rough shape / object / model and convert to polygon mesh to continue working and fine tune The same problems do not exist for Polygon modelling and the hole can be filled easily in tons of different ways like, "fill hole", "selecting an edge and using fill hole", "bridge", "Merging vertices"... Hope Nurbs get something like this one day. They have holes too!