Add Thickness to NURBS

# 1 08-08-2012 , 01:18 PM

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I have created a curve and used a circle to extrude along it and create a surface.
I want to now add thickness to the inside of the 'tube' that has been created.
Is that possible without converting to polygons and if so how...?

The way I thought I would be able to do it is to select the circular Isoparm at the end of the tube and then create another circle and use the loft tool, but this doesn't want to work and just creates a very ugly face capping the hole rather than adding thickness.

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# 2 08-08-2012 , 05:13 PM

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make a smaller nurbs circle for the inner diameter and then extrude that along the original curve.

now you have two concentric tubes that follow the original curve.

Select the outer and inner isoparms at the end of the tube surfaces and do a planar.

now you have a capped tube but with very sharp edges so ...

Select the round tool and apply a round to the inner and outer edges of the end of the tube.

Don't worry if you see gaps in the UI display. You fix those by either adjusting the render tessellation in maya software (which is a pain) or by rendering in mental ray and using a surface approximation node.

You should end up with 5 surfaces. The outer tube, the inner tube, the two rounds, and the trimmed planar surface and should look something like what you see below. Notice the UI image has visible gaps where the surfaces meet but the mental ray render looks clean.

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"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

Last edited by ctbram; 08-08-2012 at 07:26 PM.

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# 3 08-08-2012 , 05:16 PM

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You will also have to add a mental ray surfaces approximation node to the surfaces to avoid gaps in the surfaces.

Although this will produce a very nice result unless you specifically need the surfaces to be nurbs the much easier solution would be to simple convert the outer surface to a polysurface and the extrude thickness and add support edges.

Now you have a single polysurface which will be much easier to work with.

"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

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# 4 08-08-2012 , 07:58 PM

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Excellent. thanks for that! Yeh it does give a nice result but I tink I might convert to polysurfce so it is all in as one object i think it keeps the scene a lot cleaner and less hidden geomitry afterwards.
Well thats another thing learnt user added image