Weird Object

# 1 08-02-2013 , 03:02 PM

Registered User
Join Date: Dec 2012

Posts: 34

Hey guys!

I have a *.stp file which I opened up in Maya. (picture 1)

I now would like to modify and edit this model, move vertexpoints, faces etc..

What am I supposed to do that I can work with this thing?

When I convert NURBS -> POLYGONS it gets even worse (picture 2)

I would greatly appreciate your help.

Thanks so much!

PhilCC

Attached Thumbnails

Click image for larger version

Name: A1Stp raw.JPG
Views: 284
Size: 174.6 KB
ID: 53350

Click image for larger version

Name: X2nurbs to polygons.JPG
Views: 275
Size: 149.1 KB
ID: 53351

Quote

# 2 08-02-2013 , 07:07 PM

Moderator
Join Date: Jan 2004

Location: Michigan, USA

Posts: 2,998

You are not going to be able to do much.

The first problem you are seeing is that when you are converting all the trimmed surfaces are re-appearing. You can select the right options in the convert tool to prevent this but you'll have to delete all the history on the object, separate it, and work on converting each piece individually.

Then the next problem you will have is all the poly tessellation will be horrible and you'll have to fiddle more with the conversion tool options for each part.

Then you'll realize you have seams all over the mesh because none of the parts edge verts will be likely to match.

and finally after lots of wasted time you'll realize converting complex trimmed nurbs parts directly to polygon meshes is pretty much a complete wast of time.

I have had some success taking the nurbs model and making it live and then manually rebuilding a clean poly mesh on top.

You can also use tools like topogun and 3d-coat, to model over the top of the nurbs form a little more efficiently then in maya. But I still have not come up with an efficient workflow to do this in any package yet.

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

Last edited by ctbram; 09-02-2013 at 07:33 PM.

Quote

# 3 08-02-2013 , 07:17 PM

Super Moderator
Join Date: Dec 2006

Location: South FL

Posts: 3,522

I was going to say, I don't know if conversion is going to be much help. You have a lot of rebuilding to do, especially looking at the bottom right area near the right hole.

- Genny
__________________
::|| My CG Blog ||::
::|| My Maya FAQ ||::

Quote

# 4 08-02-2013 , 07:25 PM

Moderator
Join Date: Jan 2004

Location: Michigan, USA

Posts: 2,998

Exactly Gen, he has all kinds of separate trimmed surfaces, with fillets and rounds so he'd end up with a mess that would be impossible to clean up.

I came from a NURB's background and have gone through this process of trying to take nurbs models and message them into polygons. What I went through above is kind of the stages you go through before you realize "I can't get there from here, damn!".

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

Quote

# 5 08-02-2013 , 07:48 PM

EduSciVis-er
Join Date: Dec 2005

Location: Toronto

Posts: 3,374

Is there an option to make a surface live and build the polys on top of the surface?

-stwert

Website - Blog - YouTube - Vimeo - Facebook - Twitter

-->How to Effectively Ask Questions on Forums<--

Quote

# 6 08-02-2013 , 08:28 PM

Super Moderator
Join Date: Dec 2006

Location: South FL

Posts: 3,522

Is there an option to make a surface live and build the polys on top of the surface?

Originally Posted by stwert

Yeah, Rick was saying that.

- Genny
__________________
::|| My CG Blog ||::
::|| My Maya FAQ ||::

Quote

# 7 08-02-2013 , 08:32 PM

EduSciVis-er
Join Date: Dec 2005

Location: Toronto

Posts: 3,374

Right, should have read the whole post...

-stwert

Website - Blog - YouTube - Vimeo - Facebook - Twitter

-->How to Effectively Ask Questions on Forums<--

Quote

# 8 09-02-2013 , 04:46 PM

Registered User
Join Date: Dec 2012

Posts: 34

Thanks a lot guys!

So I will give it a try and rebuild it over this mesh with polygons.
Would you propose to do it in a way similar to having blueprints and then just model?

I did not do that original mesh, can you tell me how it was done and why it was done so messy without any options to edit it afterwards?

Quote

# 9 09-02-2013 , 07:53 PM

Moderator
Join Date: Jan 2004

Location: Michigan, USA

Posts: 2,998

Right start with the rings of polys around the holes and work outwards. You can also start with the rings of polys around the holes then create strips of polys along the outer edges and then work on bridging between them.

It can be a tedious process and there is a bit of planning involved to work out the the correct number of polys in the rings and strips so they match up.

Here is something that may help...

Take the object you want to make live and apply a blinn material to it and make it slightly transparent and finally make it live. This will help you see the polys as you as you create them on top of the live surface.

What I usually do is create a starting polygon and then extrude an edge off that polygon. You have to remember to then move each vertex as the newly created edge will have its center point snapped to the live surface and not the two end verts.

So you extrude an edge then jiggle the verts to snap them and repeat this over and over. As I said it's a tedious process.

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

Last edited by ctbram; 09-02-2013 at 07:57 PM.

Quote

# 10 09-02-2013 , 10:57 PM

Registered User
Join Date: Dec 2012

Posts: 34

Ok i think I can get that right.
Seems like a similar process to rebuilding a face with polygonplanes right?

I have to build it very 100% precisely and form-true. I have exact guidelines on the dimensions.

What is the Best way to get perfect round holes because if i build planes around it will get a bit buckled.

And is there a good way I can build the object (especially the holes) to afterwards be able to transform it. Let's say I would need one radius of the hole to be bigger or smaller and i would like to move the holes. Is there a way to do so without destroying the whole mesh?

Already thank you again! That helped a lot.

Quote

# 11 09-02-2013 , 11:31 PM

Moderator
Join Date: Jan 2004

Location: Michigan, USA

Posts: 2,998

You can use a nurbs circle as a reference to align the verts of the loop around the hole. You can also use a cylinder pushed into the surface as a guide object.

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

Quote

Weird Object

Posting Rules Forum Rules

Similar Threads

Topics

Free Courses

Full Courses

VFX News