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How does importing CAD models work?

Hello,


  I'm currently reviewing the Vortex Studio documentation and guides as a pre-purchase evaluation. I found some information on importing CAD models, but the documentation seems very light on specifics. 


  For example, what specifically is imported with the CAD model? Is it just geometry? Can I import a complete assembly or do I have to import an assembly piece-by-piece? Are constraints preserved or do I need to manually reassemble after import? 


  What about materials? Are the masses, moments of inertia, etc. imported? What controls the graphics of the final product? It looks like Vortex Studio supports physics based rendering, but Solidworks is maybe not the best tool for PBR creation and editing. Is it possible to overwrite appearances with an imported CAD model? How are Solidworks decals handled?


Thanks,


  Chuck


Hi Chuck,


I'm less an expert in graphics, but I can answer some of your questions.


The CAD import is only used to create graphical models for use in Vortex, not physics. There is no direct import of mass properties or constraints. The goal of the feature was to provide a path from CAD files to graphical models without requiring an expert in a graphical modelling tool like 3DS Max.


The hierarchy of the CAD model (parts and assemblies) is converted into an equivalent hierarchy of graphical nodes and sub-nodes in Vortex's Gallery (Vortex's graphical format), and each node can be defined to move with a corresponding physics part. 


Vortex does have a very simple procedure to generate the physics parts from graphical nodes, so that names and transforms are automatically taken from the graphics gallery (which came from CAD or a graphical modelling tool). There are also simple steps to create collision geometries and estimate moments of inertia from the nodes. 


Martin


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Fair enough. How is texturing or rendering performed? Do the appearance and materials transfer with the CAD model, and how would you edit those properties? The graphics guide states, for "Making further corrections to a 3D model," that it's possible to export and re-import 3D models and textures. There's a caveat that states (.fbx format only) - does that mean you can only export something that was originally in FBX format, or does it mean that you can export any model, but you can only export in FBX format? Does the same apply to textures (they can only be exported if the model was in FBX format?) 

A CAD model imported into a gallery will contain geometry, but CAD model geometry is generally far too detailed for real-time simulation. The import process reduces the complexity with some automatic algorithm enough so that it can be used in Vortex, but a high-quality, efficient model for graphical simulation probably will require some more sophisticated tools and people who know how to use them.


While the CAD import will get you some geometry, it doesn't do much with textures. I believe the CAD imports are not even unwrapped, so could only use solid colours. 


Our general workflow to build the Gallery starts with importing geometry from a 3D graphical tool. Simple textures (albedo only), will be imported automatically. But for more sophisticated material properties (emission, occlusion, specular, normal, height, etc.), the texture layers are imported and assigned individually. All of this is stored in the Gallery. Any of these geometries and textures can be re-imported and replaced later.


I'm not sure about the ability to export models. We've recently switched libraries for the CAD functionality (now using PiXYZ), and we're still updating documentation. 

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