Importing Lightwave objects into Mastercam.

[Tomasz Winnicki]

Hello.

 

I'm using an older version of Lightwave (7.5c to be exact) to create an organic 3D model. Does anybody know of a good way to import a Lightwave .LWO file into Mastercam X2? Some time ago I've exported .DXF files from Lightwave and imported them to Mastercam but always lost surface data; had only the wire frame. It might not be so bad to recreate the surfaces if the object had only a few hundred polygons but this object I'm working on now has to be smooth and detailed and will probably end up being several thousand polygons.

[Guest CNC Apps Guy 1]

Can you export IGES or VDA from Lightwave? Either one of those should give you a surface file in MC.

[Guest CNC Apps Guy 1]

Also, if you can, download the evaluation of Rhino, you can read in your lightworks file and export as IGES, and a host of others. You get like 25 saves/exports.

[Tomasz Winnicki]

Thank you for your reply.

 

I downloaded the Rhino evaluation demo and tried your suggestions, however it didn't work. Rhino loaded the Lightwave object correctly but when I tried to convert to IGES I received the following message:

Rhinoceros 4.0 IGES Export Warning

IGES export type "Mastercam X" does not support polygon meshes. 1 polygon mesh was not exported.

 

When I exported to VDA format the file was only 2K. That just can't be right because my mesh has 61440 faces. Mastercam didn't load anything when I loaded it.

 

Mastercam X2 has Rhino's format 3DM listed in the suported file types. I saved my object in Rhino 2, 3 and 4 but Mastercam was blank, zero entities, after loading.

 

I also tried some other formats like Parasolid X_T (got similar message as for IGES), ACIS SAT, STEP, DXF, DWG (imported only edges) but none of them worked. Most of those formats have some advanced options available when saving. I accepted the defaults or picked obvious choice of Mastercam when saving. Perhaps one of the above formats might work if set with different options. There are very many combinations and I'm pretty much out of my 25 available saves in the Rhino demo. Any ideas?

 

I used Lightwave subpatches to model my object. The subpatch cage has only 960 faces (61440 after 'freezing' with 8 subpatch divisions). Perhaps there is a way to import the subpatched Lightwave object into Rhino and have it converted to NURBS type compatible with Mastercam.

[Pete Rimkus from CNC Software Inc.]

In Rhino there's a "Polysurface from Mesh" function. I bet that'll help. Run that on the mesh and then save the resultant file (which should now contain surfaces) as 3DM or IGES so you can take it to Mastercam

 

We added support for importing Rhino mesh entities in Mastercam X3.

Of course, there's not much you can do with them, though - we added a new polygonal mesh entity in X3 and that's what they come in as.

[Tomasz Winnicki]

This is a little belated, but thank you Pete, your suggestion worked. Although it is not the ideal solution but it will let me finish my current job.

 

The problem with this solution is that "Polysurface from Mesh" converts every single facet/polygon into a separate NURBS surface. There's a 20000 faces limit and the object remains faceted. If the object contains thousands of polygons it slows some operations in Mastercam to a crawl, even on a relatively fast computer. It would be ideal if Mastercam could 'simply' (I'm just writing 'simply' but I know the implementation would most likely be very complex.) import Lightwave's subpatch (or it might be called meta-NURBS if I recall) control cage object and convert it to Mastercam's NURBS surface object keeping the smoothness.

 

Here's a followup question. If it was required to keep the smoothness of the object, what would be a good way to convert Lightwave's low polygon subpatch cage object into a Mastercam NURBS object? It should be noted that even a 'low polygon' cage can still contain thousands of polygons so preferably you'd want to avoid doing it manually.

[BernieT]

quote:

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what would be a good way to convert Lightwave's low polygon subpatch cage object into a Mastercam NURBS object?

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If your mesh part is fairly simple Rhino has a few tools to put surfaces on a mesh.

 

Try the 'Drape' command - it will lay a nurbs surface over the mesh. You then have to trim it. By doing this over the top and then the bottom you will have a surf model.

 

Also you can use 'curve-curve from objects-contour' to create sections thru the mesh which can be used to 'loft' a surface.

 

Like I said, this works for simpler parts.

 

HTH

 

check this thread