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Softwares like Catia, SolidWorks or the like all can visualize complex models while designing.

Exporting such models to raster triangle meshes yields huge files that later need to be greatly simplified to be imported into 3D engines like Unreal Engine or equivalent.

My question is: how do they visualize such complex geometries without rasterization? How do they do it that fast?

Dean
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  • Can you please define what "rasterization" means to you? If you mean simplifying exact geometry to triangle meshes for visualization purposes then CATIA does this of course. All surfaces are visualized by triangle meshes and all curves a visualized by polylines. The maximum deviation between the exact geometry and the meshes can be specified. For huge assemblies LOD (level of detail) techniques can be used. In general the visualization requirements of CAD systems are less demanding than certain games. – gdir Jun 20 '17 at 13:35

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GPUs can only deal with triangles, therefore they tessellate geometry exactly as for STL export. Tessellation tolerance may vary from display to STL export affecting the time required to compute it.

abenci
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Exporting such models to raster triangle meshes yields huge files

Not entirely correct. When you ask solidworks for the mesh you also provide quality that will influence number of triangles you receive - can be millions, can be just a dozen.

CAD packages operate with most bodies/shapes analytically - they have a formula. My guess is any other 3D engine does the same, the thing is format of the analytical data that different engines use is not the same. So you need to convert from one to another using triangles, format that everybody understands.

Vlad
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