Bevelling Nurbs Edges

[korthuran]

If you're not going to be adding any more geometry to that area you are probably better off waiting to bevel it until you convert it to polys. It will give you more precise control.

With just nurbs I would loft through the bevel. That is I would have the loft start at the first curve, when it gets to the curve that creates the right angle it goes through that one and on to a smaller scaled curve of the same shape. The closer the smaller curve is to the same size and shape the crisper the edge will be. If it still is a right angle then it means you need to adjust the loft setting. With nurbs you can loft in different settings and one setting is a direct connect with no allowance for a curve. Another setting is much more organic. I can't give specific names and what not as I rarely work with Nurbs.

[mwilding]

Thanks for the reply. I can't find the setting you are talking about in the loft functions. I wasn't planning on converting it to polygons but I suppose I could if I had to but would prefer to find a way to do it in Nurbs if I can.

[mwilding]

I am absolutely stumped with this. Surely there is a way to do this without me having to model it in Polygons? Please any suggestions I would be forever grateful, on a bit of a time limit. :scream:

[phix314]

Select one Isoparm, select the adjacent isoparm, Edit Nurbs -> Round Tool. May take a few tries. Selecting adjacent isoparms sucks ;)

[JasonA]

I know exactly the problem you'r talking about . I've found that neither Studio nor Maya handle filleting complex nurbs surface connections very well. This is totally unlike a solid modeler (like ProE, Solidworks, etc) which shred this sort of thing without blinking.

One key thing to try is if you're going to use the round tool, then make sure you're rounding all of the edges that connect to each other all at once. This can sometimes work.

However, the way I've always worked around this sort of thing is (and you're gonna hate to hear this) - you have to build your fillets manually. This is incredibly tedious, but produces the best results. The way I do it is to use the round tool (or fillet tool whichever) only temporality to generate new curves on surfaces which I can then offset off the surface and use to birail or square in the fillets.

Hope that makes sense. If you want, upload your file and Ill show you what Im talking about.

[mwilding]

Thanks guys. JasonA that sounds like the best plan. How much do you normally offset your rounds or fillets by? Will doing that produce a nice edge on the corners where I will have 6 isoparms meeting, not sure how I will get that nice blend that goes over the corner as well as along the edge. Not at my computer today but will be working on it all day tomorrow to get it finished.

[JasonA]

How much you fillet your radius depends on your scene scale (and from an asthetic point of view is really up to you). IIRC the round tool will actually show you a small arc thats a preview of the round radius so you can get a sense for how big it will be before you actually apply the tool. Remember the select ALL of the sharp edges on your model and do the round at once, or it will likely fail at one or more corners.

In terms of the isposarms densit yaffecting this procedure, that really wont matter much because when you run the round (or fillet) tool, because it creates a trim curve on the surfaces that you're rounding. Those trim curves are what I offset to use as new rail curves for all the surfaces. Bear in mind that in an ideal workflow (no trims) this workflow requires you to end up recreating ALL of the surfaces, not just the fillet. Its like you use the round/fillet tool temporarily to help you create a new curve network from which you can rebuild the entire object, but without trims but that have radii on all the edges.

[mwilding]

Still haven't managed to acheive this without converting to polygons and now it is becoming something of pride that I figure out how to do it. When I try and do a round on all connecting edges the trim removes the main shape. When I just do round on half the shape (with the aim of duplicating) it doesn't match up properly because each half is made in two pieces, although I have tried doing halves in a single but with the same effect.

The closest I have got is by doing each quarter with a round but the second quarter doesn't trim properly leaving the main shape going over the round instead of joining it.

This all means I haven't been able to get a decent shape to do JasonA suggestion. Any more help would hugely appreciated.

[JasonA]

Its tricky to say what you'll have to do to get the edges fillet. Maybe post your file, so someone can have a go at it and advise

[mwilding]

I have posted the file, there is just one half (going to duplicate) of the outside skin there so will need offsetting. I have also got the curves created for all the shapes taken from the trim edges. I was playing with new ways of trying to skin it creating extra curves but haven't found anything suitable. Would be greateful if you would have a quick look.

[/url][url="http://www.filefactory.com/file/fc51d9/n/Outside_Engine_2ndTry_mb"]Outside_Engine_2ndTry.mb (http://%5Burl=http://www.filefactory.com/file/fc51d9/n/Outside_Engine_2ndTry_mb%5DOutside_Engine_2ndTry.mb%5B/url%5D)

[JasonA]

I think you're biggest issue here was that you have many duplicate surfaces sitting on top of one another. Other than that it worked out fine. Here's your file, redux and I included a text file explaining what I did at each step.

[mwilding]

Jason thank you so much, that is brilliant. I have read through but will go through and do it all myself tomorrow. Not sure how you project the fillet surface though, would you mind letting me know. I shall get that dvd tomorrow as well.

Thank you again.

[JasonA]

hey my pleasure, glad I could help!

With regards to the projection of the fillet edge... Often times when using round or fillet, the main flat surfaces won't get trimmed away properly (unless you're modeling something with perpendicular ends, like a box) because the curve on surface generated by the tool doesn't extend all the way to the edge of the surface, thus cause the auto-trim to fail. so you end up with a fillet, but the flat edge not trimmed, and no remaining curve on surface (I think the tool automatically deletes it).

So to recreate it, first select the large flat surface, then with that selected, right click over the fillet surface and go to isoparm mode and shift select the edge of the fillet surface thats touching the flat surface that didn't get trimmed. Now go into the Project Curve tool option box and change the default projection type from view to normal and wolah project the curve. This works because the fillet edge is right up against the flat surface so the projection curve ends up right where it should be. You'll see at this point why the original trim failed when you used the round tool - look at the curve on surface... it doesn't go all the way to the end. No problem though, just drag it over, and then you can complete the trim.

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