[Carrara]import dxf from CAD looks bad - Polyloop

dooki · 28th November 2007, 20:46

Hey all,

I'm using this CAD app for modeling and only exports that Carrara will read are IGES and DXF. The CAD app does export obj. Nothing shows with IGES and the DXF looks like crap (please attached image).

- Why does it look like this? You can see the tri's of the geometry.
- How can I get my CAD model into C5 to render?

Thanks.

-Dooki

jbshorty · 28th November 2007, 21:29

Hi Dooki. I don't really use Carrara. But to me it looks like the vertex normals are smoothed. This is preferred on a CAD model when all surface joins are C1 (for example when all joins are filleted), but can be a disaster if your surfaces are C0 (for example with a chamfer or a left with a sharp edge). at C0 joins, smoothed normals will create a banded effect like you have here. Check the export options of that other program (ViaCAD?) and see if you can turn off normal smoothing. Of course this might make all the mesh faces noticably faceted in your render (at least will not have the black banding). Or you can explode the object before exporting, then reassemble the mesh in Carrara. Or you can fix it properly and fillet all your joins before export (NOT fun though

!)

shorty

Piem · 28th November 2007, 22:35

Quote:

Originally Posted by dooki

- How can I get my CAD model into C5 to render?

Thanks.

-Dooki

export in nurbs , not polygonal
and use the carrara 's nurbs tesselation function

dooki · 29th November 2007, 06:56

THanks.

Piem: Cannot export NURBS.
Shorty: Yes Viacad. No, cannot adjust export. Hey I sent you message on Viacad.

-Dooki

jbshorty · 29th November 2007, 07:12

I think ViaCAD can export both IGES and STEP files, which both support NURBS. Did you try either of those?

If not, then you can fix the normals in Rhino using the various mesh welding tools. Basically what you need to do is unweld all the vertices along those C0 edge joins...

shorty

Eddi · 8th December 2007, 06:01

Hi dooki,
i am using step (AP203) and stl for geometrie transfer.

After geometrie import i smooth the object with an angle greater than 20...30°.

Eddi

bwtr · 8th December 2007, 07:51

Both Iges and DXF import from ViaCAD into Carrara 6 beautifully.
And adjustment can be made to the iges export in ViaC also.

Eddi · 8th December 2007, 18:57

My iges import is not very well, because my object is a group with hundrets of surfaces. I can't define any morphing targets. The imported step object is ONE surface.

28th November 2007, 20:46	#1 (permalink)
dooki Box modeling Join Date: Feb 2005 Location: Northern Calif. Posts: 259 My Photos: (0)	[Carrara]import dxf from CAD looks bad Hey all, I'm using this CAD app for modeling and only exports that Carrara will read are IGES and DXF. The CAD app does export obj. Nothing shows with IGES and the DXF looks like crap (please attached image). - Why does it look like this? You can see the tri's of the geometry. - How can I get my CAD model into C5 to render? Thanks. -Dooki Attached Thumbnails __________________ PC/ P4/ /XP/ 2.4GHz/ 512RAM/ ATI Radeon 9550/256RAM Macbook Pro/Leopard/2.4GHz/4RAM/NVIDIA 8600M (256MB) eMac/ G4/Tiger/ 1.25 GHz/ 768RAM/ ATI Radeon 9200

29th November 2007, 06:56	#4 (permalink)
dooki Box modeling Join Date: Feb 2005 Location: Northern Calif. Posts: 259 My Photos: (0)	THanks. Piem: Cannot export NURBS. Shorty: Yes Viacad. No, cannot adjust export. Hey I sent you message on Viacad. -Dooki __________________ PC/ P4/ /XP/ 2.4GHz/ 512RAM/ ATI Radeon 9550/256RAM Macbook Pro/Leopard/2.4GHz/4RAM/NVIDIA 8600M (256MB) eMac/ G4/Tiger/ 1.25 GHz/ 768RAM/ ATI Radeon 9200

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28th November 2007, 21:29	#2 (permalink)
jbshorty proud to be a nurb Join Date: Jul 2006 Location: only in your mind Posts: 1,260 My Photos: (0) Images: 1	Hi Dooki. I don't really use Carrara. But to me it looks like the vertex normals are smoothed. This is preferred on a CAD model when all surface joins are C1 (for example when all joins are filleted), but can be a disaster if your surfaces are C0 (for example with a chamfer or a left with a sharp edge). at C0 joins, smoothed normals will create a banded effect like you have here. Check the export options of that other program (ViaCAD?) and see if you can turn off normal smoothing. Of course this might make all the mesh faces noticably faceted in your render (at least will not have the black banding). Or you can explode the object before exporting, then reassemble the mesh in Carrara. Or you can fix it properly and fillet all your joins before export (NOT fun though !) shorty

29th November 2007, 07:12	#5 (permalink)
jbshorty proud to be a nurb Join Date: Jul 2006 Location: only in your mind Posts: 1,260 My Photos: (0) Images: 1	I think ViaCAD can export both IGES and STEP files, which both support NURBS. Did you try either of those? If not, then you can fix the normals in Rhino using the various mesh welding tools. Basically what you need to do is unweld all the vertices along those C0 edge joins... shorty

8th December 2007, 06:01	#6 (permalink)
Eddi Vertex Join Date: Jan 2006 Posts: 7 My Photos: (1)	Hi dooki, i am using step (AP203) and stl for geometrie transfer. After geometrie import i smooth the object with an angle greater than 20...30°. Eddi

8th December 2007, 07:51	#7 (permalink)
bwtr Brian Join Date: Jul 2005 Location: South Australia Posts: 2,042 My Photos: (6) Images: 49	Both Iges and DXF import from ViaCAD into Carrara 6 beautifully. And adjustment can be made to the iges export in ViaC also.

8th December 2007, 18:57	#8 (permalink)
Eddi Vertex Join Date: Jan 2006 Posts: 7 My Photos: (1)	My iges import is not very well, because my object is a group with hundrets of surfaces. I can't define any morphing targets. The imported step object is ONE surface.