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Reduce Mesh Failure

Message 1 of 10
3890 Views, 9 Replies

Reduce Mesh Failure

Hello everyone.
I am trying to reduce the faces on a mesh in order to then do Mesh to BRep. I am following the steps outlined here:

I get everything fine up until the moment when I'm supposed to select the meshes I want to reduce, which it won't let me do. To clarify: the reduce mesh settings dialog box is all set-up properly, my meshes appear in the model space and in the "Bodies" list, however they don't get selected when I click on them. What should I do? 

Many thanks! 

Message 2 of 10
in reply to: Anonymous

In fact, I cannot seem to modify these meshes in any way whatsoever. None of the options from the "Modify" tab seem to work on them when it comes to selecting these bodies. 

Message 3 of 10
in reply to: Anonymous

@Anonymous wrote:

What should I do? 

1. Share your design

2. Use Autodesk Meshmixer 😉


Message 4 of 10

Yes, as @TrippyLighting says, we cannot help you without seeing your design.  A couple of more questions:


  1. Are you working with a parametric design?  If so, do you have more than one Mesh feature in your timeline?  Mesh operations are scoped to bodies belonging to the active mesh feature
  2. Is your mesh a quad mesh?  The mesh workspace in Fusion only operates on triangle meshes.  You can choose to triangulate quad meshes on import if you want.  However, if you do have a quad mesh, then I would recommend converting that mesh into a TSpline - TSplines are much easier to work with
  3. Do you really want to Reduce the mesh, just to convert it to a BRep?  What do you want to do with the result?  Do you want to do precise operations such as Hole or Fillet on the result?  Unless you want to do BRep operations on the result, converting a mesh to a BRep is not a good idea - the result contains one BRep face for each mesh facet, and is often slow and imprecise to work with.  If all you want to do is, say, scale the body and 3D print it, use Meshmixer, as Peter suggests


Jeff Strater
Engineering Director
Message 5 of 10
in reply to: jeff_strater

Thank you for your reply, I'm not 100% confident in my answers but I'll give it a go:
1. AFAIK the model I'm using was designed in 3DS, so I assume it is a parametric model. I am still slightly uncertain on how the Design Timeline works but I guess that as I inserted the model to Fusion360 in its complete state, there shouldn't be much to work with there? 

2. I'm having trouble converting it into a TSpline as: A. I cannot manage to make the "sculpt" tab show up from which to select the convert tab (this is the only way I've seen to do it in the online tutorials I found) and B. This mesh is WAY over 10k facets so I assume it wouldn't be able to do that to begin with. How would you go about doing this?

I did triangulate my meshes after reading this, so I assume it was in quad mesh to begin with and it did allow me to Reduce the mesh but the result was completely distorted and had ruined the forms of my model. 

3. The reason I want to convert it into a BRep is that I'm trying to export/link this model to other applications, primarily Revit, and I read on the Autodesk forums that Revit supports BRep solids. For my purposes, there will be little to no editing on the model once it is exported/linked so all I've been trying to do is make it "lighter" and get it in a format that's easy to work with. I've downloaded MeshMixer, as you guys suggested and will have a look to see what I can figure out (never used it before). 

Thanks for all the help so far.

Message 6 of 10
in reply to: Anonymous

P.S. I already sent Trippy Lighting a private message with my model, but the Forum won't allow me to send another Private Message (something about an allowance) so perhaps you can get it off him? I've purchased the model from TurboSquid so I'm concerned about copyright restrictions with posting it here publicly. 

Message 7 of 10
in reply to: Anonymous

The model is a complete city scape with over 600,000 faces and over 1.3 million triangles. It is unlikely that this ever was a pure quad mesh, but it would not have made any difference anyway.


You will not be able to convert this into a T-Spline.

You will not be able to convert this into a BRep.


The number of faces is needed to describe the sheer number of small geometric shapes of all the buildings and structures that this city scape is comprised off. Trying to reduce the mesh density is obviously going to destroy the detail and nature of this mesh.


Screen Shot 2018-08-06 at 3.25.26 PM.png



Message 8 of 10
in reply to: TrippyLighting

Thank you for the concise answer. Is there any way whatsoever in which I can manipulate this mesh in Fusion360 in order to converit it into a solid that can be exported as .SAT (it's the only Fusion360 export format that I can insert into Revit)? 

Message 9 of 10
in reply to: Anonymous

Not with Fusion 360 or any method I know.


Even if all the little building blocks in the design would be solid models, this would be a file with thousands of solid bodies and Fusion 360 would probably chock on this as well as I suspect Revit would.


Message 10 of 10
in reply to: TrippyLighting

Thanks a lot, I appreciate the explanations. It seems like I've been going about this the wrong way. I'll mark this Answered.

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