Fudge
03-20-2005, 07:48 PM
hey im new with nurbs and i cant seam to figure out how to delete half a nurb sphere, thanks
Fudge
Fudge
View Full Version : delete nurbs?
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stallion151
03-20-2005, 08:59 PM
first select an isoparm where you want the nurbs to be cut, then edit nurbs> detach nurbs surface, and it should break it from where the isoparms met.
alexx
03-21-2005, 02:40 PM
hehe :)
very new to nurbs indeed.
read some about nurbs online and in the manuals because they are quite a lot different from poly models.
just always have in mind that they are mathematically defined surfaces. simply deleting or appending patches is not easy as you would do it with polies.
cheers
alexx
very new to nurbs indeed.
read some about nurbs online and in the manuals because they are quite a lot different from poly models.
just always have in mind that they are mathematically defined surfaces. simply deleting or appending patches is not easy as you would do it with polies.
cheers
alexx
wiredgear
04-03-2005, 07:49 AM
ok, I right click on the nurbs sphere and select "isoparm" and then I select half the sphere so then I can go to /edit NURBS/Detach Surfaces and when I do try to detach, it won't let me....? any ideas of what i'm doing wrong?
JYoung
04-03-2005, 07:58 AM
Works fine for me. Make sure you have an entire ring(2 isoparms) selected when detaching.
Jerocide
04-03-2005, 08:53 AM
ok, I right click on the nurbs sphere and select "isoparm" and then I select half the sphere so then I can go to /edit NURBS/Detach Surfaces and when I do try to detach, it won't let me....? any ideas of what i'm doing wrong?
an isoparm is the lines that make up the model (visible in wireframe mode). after going into isoparm mode, they turn light blue i think. Select the one where you want the split to be. It will turn yellow. Now go to detach surfaces. Now you will have two surfaces. One on each side of the isoparm.
an isoparm is the lines that make up the model (visible in wireframe mode). after going into isoparm mode, they turn light blue i think. Select the one where you want the split to be. It will turn yellow. Now go to detach surfaces. Now you will have two surfaces. One on each side of the isoparm.
wiredgear
04-03-2005, 09:11 AM
thank u very much jerocide! Muchly appreciate u helping me understand about isoparms. Didn't actually know what it was. Thx again!
Pete2003
04-03-2005, 02:46 PM
Just to add, if you just wanted half a NURBS sphere to begin with you could define this in your creation options. Theres a setting in there which is set to 360degrees which defines the 'full sphere'. Setting this to 180 degrees will create a semisphere to begin with.
Pete.
Pete.
Emil3d
04-03-2005, 06:24 PM
And I will just add a little bit of depth to this issue.
Nurbs always have 4 border edges defining each surface along 2 directions - U and V. Depending how the opposite borders of a single surface meet, the surface can be Open, Closed, and Periodic which Attribute Editor displayes in the FormU and FormV fields in the first section of the Shape node for each selected surface.
Periodic (also called Continuous) is when the edges are attached and glued together in such way that if you pull a CV on the seam it will not open a gap.
Closed is when the edges meat each other in a perfect tangency so no seam is visible when rendered, but they are not glued together so when you pull a CV on the seam it will open a gap.
Open is simply when the edges don’t meat each other.
When you Detach an Isoparm from a Periodic (continuous) direction on a surface, technically you are detaching it but the result will be one Closed surface and on practice this will look like as if you have only moved the Seam. The major change although not obvious at first is that this turns the surface from Periodic to Closed and for someone who doesn’t know what’s going behind the scene may conclude that the surface doesn’t detach at the first try.
Once you have a Closed surface, performing Detach in the closed direction will break it into 2 surfaces.
A default NURBS sphere in Maya is build by closing periodically (continuously) the opposite edges in the V direction and the edges in the U direction are opened and pinched to single points at the poles.
Now if you detach an isoparm in the V direction you will not have 2 separate pieces since this turns one continuous surface into a Closed one (like cutting a ring with a saw) you detached but it is still one surface. Second detach (cut) will brake the one surface into two.
Also there’s one limitation that will not allow you to outsmart those rules if you try to cut the sphere along the seam by selecting the isoparm on the seam along with the opposite isoparm.
The limitation is that if you select the seam along with other isoparms Maya will ignore the seam selection and will detach only along the other isoparms.
Hope this clears the mystery a bit.
Nurbs always have 4 border edges defining each surface along 2 directions - U and V. Depending how the opposite borders of a single surface meet, the surface can be Open, Closed, and Periodic which Attribute Editor displayes in the FormU and FormV fields in the first section of the Shape node for each selected surface.
Periodic (also called Continuous) is when the edges are attached and glued together in such way that if you pull a CV on the seam it will not open a gap.
Closed is when the edges meat each other in a perfect tangency so no seam is visible when rendered, but they are not glued together so when you pull a CV on the seam it will open a gap.
Open is simply when the edges don’t meat each other.
When you Detach an Isoparm from a Periodic (continuous) direction on a surface, technically you are detaching it but the result will be one Closed surface and on practice this will look like as if you have only moved the Seam. The major change although not obvious at first is that this turns the surface from Periodic to Closed and for someone who doesn’t know what’s going behind the scene may conclude that the surface doesn’t detach at the first try.
Once you have a Closed surface, performing Detach in the closed direction will break it into 2 surfaces.
A default NURBS sphere in Maya is build by closing periodically (continuously) the opposite edges in the V direction and the edges in the U direction are opened and pinched to single points at the poles.
Now if you detach an isoparm in the V direction you will not have 2 separate pieces since this turns one continuous surface into a Closed one (like cutting a ring with a saw) you detached but it is still one surface. Second detach (cut) will brake the one surface into two.
Also there’s one limitation that will not allow you to outsmart those rules if you try to cut the sphere along the seam by selecting the isoparm on the seam along with the opposite isoparm.
The limitation is that if you select the seam along with other isoparms Maya will ignore the seam selection and will detach only along the other isoparms.
Hope this clears the mystery a bit.
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