Full Version: Missing faces

Dear Michael, (or whoever can illuminate me)


I am trying to incorporate MoI into a workflow where I get CAD data from clients and make interactive Marmoset scenes out of them.
For this I imported a step model into MoI, deleted a bunch of faces and booled off a few areas which where on the inside.
I was completely done, everything looked fine in MoI, just as I wanted.



Then I wanted to import the model into Cinema4D (I found it has the best meshing algorithm around for my taste), but it was missing faces I did not delete after the import.
A short test verified that it is not an import problem from Cinema, as I imported the final 3dm file into a blank scene within MoI again and its missing the exact same faces:



Also, if I export the very first 3dm (where I hadnt booled yet) as STEP and import that into Cinema4D, everything works fine.
(Though the unoptimized mesh would be too heavy for interactive rendering...)

I can not send you the file, as it is under NDA. Would anybody have any idea what causes this behaviour and how to fix it?


Best regards,
Gustav

Image Attachments:
MoiMissingFaces_01.jpg  MoiMissingFaces_02.jpg 

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Hi Gustav, it's very difficult to figure anything about file import/export without being able to test with the actual file. If you want to keep it private you can e-mail it to me at moi@moi3d.com .

It could be something like the problem faces had a damaged trimming boundary from the beginning but it wasn't immediately apparent until after a round trip through .3dm format. But I don't currently have any examples of that over here so I can't really tell anything for sure without testing the actual problem file.

- Michael

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Hey Michael, thank you for taking your time to respond!

I am sorry to make it more difficult by not providing the model, but I legally can not. Even parts of it.
So that is out of the question.

As I stated earlier, importing the STEP I got from my client into MoI, then immediatly exporting it again works fine.
So I do not believe that the model itself has such grave problems.

I reverted back to an older export which has different problems, but those are fixeable.
Here you can see a STEP, imported into Cinema4D after heavy work in MoI.
It has remnants of bool objects in it, but I can delete those.



The only really big thing I did between this export and the one you saw earlier is that I went through all objects and joined them one by one.
(I had screwed up the import settings in C4D the first time and all faces came in as seperate objects. I initially thought it was MoIs fault, thats why I did that.)

I dont know if there is anything else to say here. Wish I could help more, so if I can provide you with any information, I am happy to oblige!

Image Attachments:
MoI_BoolObjects.jpg 

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Hi morph3us, what happens if you export out from MoI as .obj format and load that .obj into Cinema4D instead of trying to load a STEP file into Cinema4D. Does that work any better?

Also what version of MoI are you using?

- Michael

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This happen also to me in many 3d model I always have errors when I use the Step files Saved by Moi3D, I export to IGES even if this mo generates many surfaces, at least in this way I don't lose the faces.

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I am using MoI version 4.0.

I exported an OBJ, as you requested and those missing parts work fine.
Now there are other areas with problems, though. (foir example see arrow 1 in the image)



I refrained from using your obj export algorithm, because in my opinion the weighting is off.
As you can see at arrow 2, big shapes are very lowpoly, while the small air vent holes on the backside are way too smooth already.


*quick edit: I exported the upper thing, which had those squashed faces, on its own. It works now! I dont know what the difference is between exporting all meshes at once to exporting one on its own, but yeah, there it is.
Still... My reasoning towards the OBJ export algorithm stands and there still seems to be a problem somewhere in this file... :(
Is there any data log where I could have a peek?


*edit2: another main reason for not using the OBJ exporter: Cinema4D makes everything almost same size quads. With your triangulation method I get a lot of expected shading issues.
(please look at the second attachment yourself, it seems this forum software doesnt let you implement images in an edit.)

Image Attachments:
MoI_ObjExport.jpg  MoI_ShadingIssues.jpg 

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Hi pafurijaz,

re:
> This happen also to me in many 3d model I always have errors when I use the Step files Saved by Moi3D,
> I export to IGES even if this mo generates many surfaces, at least in this way I don't lose the faces.

Do you have an example file you can send to me so I can reproduce the problem over here?

- Michael

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You have also this thread about Spline from Moi to C4D.
https://moi3d.com/forum/index.php?webtag=MOI&msg=10172.1

C4D accepts also "NGone" !

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Hi morph3us,

re:
> I refrained from using your obj export algorithm, because in my opinion the weighting is off.
> As you can see at arrow 2, big shapes are very lowpoly, while the small air vent holes on the backside are way too smooth already.

You can use the "Divide larger than" option in the meshing options dialog to help with that. You can put in a distance value there and that will make any polygons larger than that size to be further refined. Use the arrow in the lower left corner of the meshing options dialog to expand it to get more options.

You can use that option to generate more uniformly diced up pieces like in this example:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2833.5


> I dont know what the difference is between exporting all meshes at once to
> exporting one on its own, but yeah, there it is.

There is no difference that I am aware of, maybe there is some difference on the receiving end.


> Still... My reasoning towards the OBJ export algorithm stands and there still seems to
> be a problem somewhere in this file... :(
> Is there any data log where I could have a peek?

It sounds like you're not making use of the export options to generate the type of mesh result you want. But it's hard for me to tell for sure since I can't reproduce anything that you're doing over here.

Sorry no there isn't any data log specific to STEP export.

- Michael

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File e-mailed now Thanks

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