Export to CAD Not Happening Soon

I have been searching for good tool to export a sketchup model to any 3D CAD format. Our company uses Sketchup Pro Ver 17 and would like a way to export to parametric modeling tool such as Autodesk Inventor. The only company listed in the Extension Warehouse reporting to provide this feature is Okino Graphics so I contacted them and was informed that exporting from a mesh moddler (i.e. Sketchup) to CAD DOES NOT WORK. Yes you can export as a 3D dwg format which looks OK however it is next to impossible to modify in AutoCAD. One would think that exporting from one Autodesk product to another should not be a problem however, this is definitively not the case.

Our engineers like to use Sketchup Pro to develop the basic model and then hand off to the CAD designers to completely reproduce in AutoCAD or Inventor. Not very efficient use of resources and hope that Trimble will put some money into developing a usable export utility. If there is anyone in the community that successfully was able to export the model in a usable CAD format I would be interested in knowing what utility was used.

Which two Autodesk products are you referring to?

• SketchUp Help Center : Using SketchUp Data with Other Modeling Programs or Tools

Inventor and other NURBS surface/solids modelers are something completely different than polygon modelers as SU or 3DS or Blender or C4D etc.

Creating freeform surfaces based on smooth and continous NURB splines a polygon modeler based on facetted meshes as e.g. SU can obviously not be used and does in consequence not support appropriate 3D CAD formats as STEP or SAT for the export:


Autodesk AutoCAD 2016 and Inventor 2016

This is the same information that Okino Graphics responded with. If this export operation is not feasible as all of the experts agree, they should not advertise as being capable of making the conversion.

At least one of us is confused! SketchUp is a Trimble product with no connection to AutoDesk, AutoCAD or Inventor. There is no “exporting from one AutoDesk product to another” involved.

SketchUp is not a parametric modeler. It is a surface polygon modeler in which everything is composed of edges and faces. Although someone might find a way to convert a surface polygon model into a parametric one, that does not sound like an easy task and is certainly beyond what one would reasonably expect SketchUp to provide itself.


It is about time that AD provides a way to import .skp into their programs…

I think that AutoCad has an import plugin available. It might not support the latest SketchUp file format, though. The SketchUp DWG exporter works quite OK, it even translates SU Solid groups and components to AutoCad Solids, but of course, it cannot address the facetting problem of curved surfaces.

which is irrelevant in this case, SU is not a NURBS surfaces/solids modeler (see above).

True. My mind jumped to Inventor, which claims to be parametric (I’ve never used it, just going by their hype). But the basic point remains: conversion from polygon surface to NURBS is also not a clean or simple operation in general.

sure, many of especially the MCAD NURBS modelers do have parametrics/constraints integrated but this is not involved in the model representation used by the kernel.

to clarify, Inventor IS parametric with 16 digit precision and a competitor
for Solid Works. We upgrades several of our AutoCAD network licenses to
Inventor as AutoCAD is NOT a 3D modeling program even though it is
advertised to support 3D.

as already elaborated above… but this has noting to do with the issue described.

Besides other things, AutoCad is a 3D modeling program. Whether it is a good one depends on your preferences. I do not generally like this part of it.

Agree, using AutoCAD for 3D modeling is a real chore hence the reason why we have switched some of our seats to Inventor which is completely different interface. Our 3D designers are able to build models very quickly once they are over the learning curve which is very steep.

OK, I must be doing something wrong but I can import a SU model into AutoCAD, using their free “Import SKP File” tool. The simple model I tested comes in as a block in AutoCAD. I explode it and it is now a mesh. I am able to use AutoCAD 2018’s Mesh tools to; extrude the faces of the mesh, to split the faces of the mesh, I can change the selection and select edges or nodes as well to manipulate. These tools have been there since about '15 release iirc.

Sure not parametric but workable. I was able to bring into Fusion 360 but I have limited knowledge about it’s usage. Maybe I should have exported from AutoCAD to .stl, .sat or igs.

As discussed earlier in this message thread SU can be converted to AutoCAD 3D format however, modifying the import in AutoCAD is a real chore. Procedurally we do not Explode the blocks due to the issues you noted. AutoCAD is not a 3D modeling application even though it is advertised as having these capabilities. I you want to model in 3D you need to upgrade to Inventor which has a totally different platform and menu structure. Yes, AutoCAD does have 16 digit precision however the program has been been updated over the years however, it is still a 2D program.

With all due respect, this statement is quite inaccurate. Some history and context is in order, at least given my own personal and professional experience; indeed, I started using AutoCAD back in version. 2.6 (mid 80s), taught courses in digital design computation for more than 20 years. I’ve been in effect addressing these topics, using both these software, AutoCAD and SketchUp (since beta of version 1).

At one point, late 80s and early 90s, Autodesk bought a company that had developed a 3D engine that ran parallel to AutoCAD (one had to Import into AutoCAD the data. They later provided an add-on, ca. version 12, called Advanced Modeling Extension, which incorporated Constructive Solid Geometry - hierarchical 3D structures, linked together via solid-modeling (a.k.a. Boolean) operations. Upon version 14 they changed CSG to B-Rep (Boundary Representation) using Spatial’s engine… Today , and for quite a while, AutoCAD has some NURBS modeling capability but fundamentally Mesh Modeling (i.e. 3D surfacing) and of course Solids.

Obviously, one does not have to “like” how AutoCAD’s UX works, what is its “3D-ness”; that’s a personal preference. But, that 3D is and has been there is unquestionable.



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The problem seems to be with SU and not ACAD. I found no “real chore” to import or edit a test SU file. There was no issue after exploding the block to edit it. After an initial explode the model was one mesh. Sure if I would have exploded again I would have been left with a jumble of 3d faces. As Diego as noted above I believe that you are in error of your statement that Autocad is not a 3D application (or not a 3D application to your definition). I can model in Nurbs, Mesh, Surface and Solids in AutoCAD. Sure it is not a parametric 3D program like Inventor or SolidWorks but it has never been advertised as such. Perhaps your engineers are in error in thinking that they can start a project in SU and then continue forward in another more robust application and not expect issues, especially one that seems to be parametric,

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