Everything related to the integration for Revit.
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By zparrish
Has anyone reported any tessellation issues when exporting their Revit model to MXS? We have an artist on the team that consistently has a tessellation issue that I can see when reviewing the exported MXS file in 3ds Max. The object name in question is:

8x4 with trim with bathroom cut out_[920981]Shape

There are also other objects that appear to have tessellation issues as well. The base object in Revit was simply a box with a void cutout. It also has some small trims near the borders with some odd faces.

When rendering directly in Revit (not Maxwell), the tessellation is fine. The only other thing I can think of is that the Maxwell plugin for Revit has some issues tessellating native Revit geometry.

Please take a look at the file and let me know if you need the original Revit file for testing. Thanks!
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By Marton Day8

The plugin doesn't make tessellation, it reads the final poly-geometry from the Revit API, but maybe there is something else.

Could you please send me the Revit file and the mxs too for checking?

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By zparrish
Sorry for the extreme delay. For some reason I hadn't received an e-mail acknowledgment from the forum system in regards to your response.

Here's a link to the Revit file which was used to generate the MSX file I attached in my previous comment. I was able to determine that the surface normals on the offending geometry were off by 90 degrees. I did so by reimporting that MXS file into 3ds Max and checking them manually.

https://constructionspecialties.egnyte. ... eMrzApAm7n

Thanks Marton!
By Marton Day8
Could you please attach an image about the problem?

I have opened the scene and I see visual issues but the behavior a bit strange and I am not sure where it comes from.

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By zparrish
Here's a screen shot from 3ds Max showing the improper normals:


If it were correct, you would see a green line pointing the same direction as the one I've noted as "This is correct". I don't have the Revit assets on my system with which to compare renderings, but I saw first hand how these tessellation issues resulted in black polygons on this object in the render, most likely because their normal calculation was parallel to its planar surface. The object in question looks fine if rendered directly in Revit, not using Maxwell. It's only after Maxwell converts the geometry that we see the issue. Thanks!
By Marton Day8
It would be good to see the original object.

What I see is only the object I can Read from the Revit API. It should be very similar to the original object but maybe not the same.

But what I see from the object now: the object quality itself is not very good for polygon modelling. Overlapped faces, not connected edges... that can be reason for wrong render results in Maxwell. I should see if it comes from the conversion or the original geometry is wrong too.

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By zparrish
Hey Márton,
I've attached a screenshot directly from Revit. I do apologize for not being able to generate test renders for lack of the additional assets, but hopefully this helps narrow it down to precisely the object in question (as seen from "3D View 4"). The object you can see was intended to be one of our wall panels (close to 1/2" in thickness), and it's placed right in front of a wall object. The artist used a void to cut the required hole through both the panel and the wall to make space for the paper towel dispenser / trash disposal unit shown below.

It's entirely possible that the original geometry was not constructed with best practices. The person who made the Revit model began as an Interior Designer and picked up Revit skills later and somewhat randomly (I think without comprehensive, formal training). It just seemed strange to me that Revit was still able to manage the original topology and normalization perfectly while the Maxwell conversion couldn't. If full re-tessellation is involved in that MXS conversion process, then it understandably would explain why this could happen. I did notice a ton of additional faces on the edge of the MXS converted wall panel object when I looked at it in 3ds Max, which I suspect is also a sign of improper base geometry.

Thanks again for checking into this Márton!

By Marton Day8
Hello Zack,

What is the current situation of this problem at your side?

I have tried to investigate it, but without good results.

I can not catch problem with the geometry from the Revit API. I mean it provides valid data, and I don't see where it goes wrong. The difficulty is that it is a multi-converted geometry - not easy to see which step goes wrong.
You import the geometry into Revit/Revit API sends it to Maxwell/from Maxwell we can import back to some other 3d application (but this is a conversion again).

I checked with other 3d apps, and all of them imported your geometry somehow differently, so I can not compare these back to the original geometry.

Could you try to check your export parameters? Or give me a screen-cap about the possible parameters?


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