Mesh to Polyface Mesh Conversion Vertices Limit (Civil3D Connector)


We’ve using a speckle workflow for passing topographical surfaces (speckle mesh) to Civil3D, but we’re running into issues exceeding the vertices limit of the polyface mesh. The number of vertices is limited within AutoCAD to a max of the 16-bit int limit (32767). The meshes we’re working with exceed this several times over.

I wanted to post and see if anyone else has encountered this issue and open up the conversation to potential work arounds, as this AutoCAD limitation caps the size of speckle meshes with which the speckle conversion method will work for. Is there a more appropriate type of mesh to convert to in AutoCAD, or should we be looking to subdivide the speckle mesh to multiple polyface meshes?

How are you currently generating the SpeckleMeshes?

They’re coming from IFC.

Hey @clrkng - just tagging you into this discussion as I know you’ve done some previous work on the Civil3D connector. Has there been experimentation is conversion of Mesh into objects other than Polymesh? Would 3D Faces be an option?

Hi! We just added support to convert TIN surface meshes back into TIN surfaces, but all other meshes are currently created as polymeshes. I can look into receiving them as 3D faces, could you describe the specific workflow that you have in mind for them?

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Basically, we’re trying to move data from a ground-modelling software and start automating the production of drawings. The workflow is exporting surfaces (large alignments of ground topography) to IFC and then use the file import service to upload to the server. The surfaces create a Speckle Mesh obj, which we are then looking at receiving into Civil3D. It is common for these meshes to have vertices in the 100k range. You’ll see when converting Mesh → Polyface that the conversion will be erroneous one vertices exceed the 32767 count limit.

Ah in that case, I can look into adding Mesh → 3DFace conversions in Civil3D for all Speckle meshes that exceed the vertex count limit :slight_smile: