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Paul Hunnicutt
Senior Member
Username: Asonearchitecture

Post Number: 337
Registered: 08-2011
Posted on Thursday, September 27, 2012 - 11:43 pm:   Edit Post Print Post

I have a NURBS loft that has some issues on the edges. When you mesh the object it is very evident. The object doctor shows no issues with the object. However some of the edges are jagged. Anyone know why this would be occurring? I have tried manipulating the control points back and forth to remove the jagged edge, but doesn't seem to help.

full NURBS loft:


wireframe on the problem edge:


shaded work on the problem edge:


renderzone on the problem edge (smoothed out):


mesh with surface analysis setting:


mesh with tight point setting:


Can I fix these from the meshed files (easy to manipulate points) and turn it back into a NURBS object? or should I up the amount of control points and try to fix it that way? It seems like the geometry is simply to "skewed" between points to make a smooth spline or mesh.

Thanks in advance. FIle is placed in dropbox with the name: AsOne-Loft Edge Problem.fmz
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Dan Shear
Senior Member
Username: Redrngr

Post Number: 722
Registered: 04-2001


Posted on Friday, September 28, 2012 - 07:48 am:   Edit Post Print Post

What about increasing the NURBS Surface Resolution first of all. Then create your NURBS surface with the Higher Surface Resolution?

Dan S.
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support@formZ.com
Moderator
Username: Tech

Post Number: 17768
Registered: 04-2001


Posted on Friday, September 28, 2012 - 10:57 am:   Edit Post Print Post

Paul,

This is a situation where you have a more extreme piece of geometry. It is very long, so even the highest setting for Simple Display resolution is not sufficient for your ribbon.

Not to worry, faceting schemes are the answer. Under the objects display resolution, set Simple to Scheme. Click the scheme name drop down and choose Faceting Schemes.... Click the + sign to add a new scheme. Set up the exact numbers of divisions you want, for example, we have used 1000 x 24.

Here is the dialog:

1

And here is the ribbon converted to polygons using the Polygon Mesh tool using the same 1000x24 settings:

2

So, you can make this grid whatever you need it to be. In this case, you need far more in one direction than most geometry would ever need. In the case of geometry with more equal dimensions, these numbers would be close to equal.

Does this help?
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Paul Hunnicutt
Senior Member
Username: Asonearchitecture

Post Number: 338
Registered: 08-2011
Posted on Friday, September 28, 2012 - 01:10 pm:   Edit Post Print Post

Sweeeeet! It looks great after using your settings. Seems to easy! Thanks!

I could not get my settings to have "faction of bounding box" to 0.0 only 0.002 Though the mesh I get looks just fine. I've mostly modeled in NURBS so meshes are new to me. Obviously I lose control points, so I will want to shape my NURBS surface exactly how I want it and then mesh the final version...correct?

It seems like I can map the meshed object just fine and it renders in Renderzone just like the NURBS object...at least during quick tests. I can also mesh the same object with holes cut out of it.

Two more issues:

1. I can't seem to thicken either the NURBS or the meshed object no matter the Thicken tool settings? Even at a small setting like 2cm.

2. I also cut lots of holes in this object and not all worked using the Surface Split tool. I grouped all the cutting objects together and it took a few hours to process. The cutting objects that did not work did pass fully through the object, same as the ones that did work. The operation left outlines, ghosted the cutting objects, but no hole in the object for 20-30% of the cutting objects. I can delete the outlines, but again no hole. If I go back and cut it again with the same cutting object THEN it works the second time around. ???

Full object with holes:


Outlines of the ones that did not cut holes (but left these outlines):


Cutting object of one that didn't work:


Outline left - supposed to be a hole like the rest:
}
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support@formZ.com
Moderator
Username: Tech

Post Number: 17773
Registered: 04-2001


Posted on Friday, September 28, 2012 - 01:29 pm:   Edit Post Print Post

Paul,

Your object is likely a bit too to complex to thicken, this tool will not complete if any condition would produce bad geometry. With an object of this size, it will be very difficult to find just what the tool is finding that it doesn't like. You may have some luck thickening it before you cut holes in it.

Also, as objects that have a great many holes added to them, the objects become less and less able to have more holes added. Also, grouping this many objects and trying to cut them all at once may be introducing problems. Try grouping smaller numbers of cutters and see if this makes a difference.

You might also simply try imprinting one of these outlines you show with the Imprint Curve tool.

You could also try the Trim/Split tool, on the the cutter blocks individually and see if they work then.

We thought you had done this number of complex holes before with a transparency map, making the whole process much easier.
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Paul Hunnicutt
Senior Member
Username: Asonearchitecture

Post Number: 339
Registered: 08-2011
Posted on Friday, September 28, 2012 - 02:31 pm:   Edit Post Print Post

No the first model was cut in the same way as I described above. The original model was built in the early beta versions of 7 last year and had a lot of geometry problems. Plus I need to make some updates/changes and I'm rebuilding the model...a lot easier now that I know more. However, I'm still running into some issues.

Can you cut an object with a transparency map? If so...do tell! That would be phenomenal! If there is a better way to get at what I'm after (NURBS ribbon cut by lots of holes) then please by all means let me know. I'm not sure a transparency map would be the solution for this project as the holes were specifically placed (in general) - though they appear random.

Actually if I go back to the original NURBS curve I find the holes are actually there (or well not there). I'm not sure what I was looking at before. They only show as holes when you use Renderzone. The infill seems to be some sort of artifact?

Shaded work:


Renderzone:
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Paul Hunnicutt
Senior Member
Username: Asonearchitecture

Post Number: 340
Registered: 08-2011
Posted on Friday, September 28, 2012 - 02:35 pm:   Edit Post Print Post

Or were you referring to using a transparency map to "cut" a hole figuratively? As in you can see through it during rendering, but it is not actually cut.

If so, I do know how to do that.

I did try thickening this in 3DS Max just to test it somewhere else (DWG export). It was able to thicken no problem there. ?
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Paul Hunnicutt
Senior Member
Username: Asonearchitecture

Post Number: 341
Registered: 08-2011
Posted on Friday, September 28, 2012 - 02:49 pm:   Edit Post Print Post

here is what I get for the object info on these outlines:





I can't assign them a surface style and I can't delete them, but again when I use Renderzone they show as holes. ?

For the record I will take your advice and break this model up into smaller pieces and do less cuts at once. Last year I still remember some cuts having this "artifact" issue though even when only cutting a few at a time. I could be wrong and will do more testing.
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Paul Hunnicutt
Senior Member
Username: Asonearchitecture

Post Number: 342
Registered: 08-2011
Posted on Friday, September 28, 2012 - 02:55 pm:   Edit Post Print Post

also if you look at the cut out pieces the Surface/Split leaves behind - there are pieces for these holes. so it is cutting the holes, but leaving these outline artifacts that are not visible with Renderzone.

If I go back and cut these problem areas one by one they all work as expected. So it seems to be as you suggest that I should break it up into smaller sections.

I appreciate all the help so far!
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support@formZ.com
Moderator
Username: Tech

Post Number: 17778
Registered: 04-2001


Posted on Friday, September 28, 2012 - 04:42 pm:   Edit Post Print Post

Paul,

Yes, OpenGL displays are not as robust as RenderZone, and objects that have lots of holes will exhibit "covered holes".

The transparency map would not actually cut the holes, it would simply show them, for these areas would be transparent. If you need to cut them, this will not work, and it is impractical if these are not random openings.

Our thickening will stop the operation if it thinks it is making bad geometry. When we run the Object Doctor and find that here is a crossing face, and as this object is one face, it will not thicken. Observing the surface as it is, it appears not to cross itself. The issue lies in the fact that this is a Trimmed Nurbs, not a pure nurbs. A Trimmed Nurbs, is a whole nurbs with a trimming modifier added, so the Thicken operation must take into account the entire nurbs. We used the extract tool on your ribbon object, and observed the upper original source spline crossed itself. Once we moved this and recreated the nurbs before it was trimmed, as 6 inch thicken worked fine. form•Z does guard against geometry overlapping, while the MAX tool may not. It is fine to thicken the model there, but you may find other issues with the object later on.

We were suggesting that trying the operations with smaller numbers of cutters grouped may help.

The image:

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support@formZ.com
Moderator
Username: Tech

Post Number: 17780
Registered: 04-2001


Posted on Friday, September 28, 2012 - 04:47 pm:   Edit Post Print Post

This is the crossing situation:

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support@formZ.com
Moderator
Username: Tech

Post Number: 17781
Registered: 04-2001


Posted on Friday, September 28, 2012 - 04:48 pm:   Edit Post Print Post

1