Materials Messing up on Reload

[Anonymous]

I have an FBX linked into my scene.  I have changed a bunch of materials in the scene, but when I go to reload the link and check "Keep scene materials parameters and Keep Scene material assignments,"  when it reloads the materials get all messed up.  You can see it in the screen shot.  If I uncheck those boxes and reload, it comes in clean, but then it erases all of the material changes I've made to my scene.  I can't keep redoing the same changes every time I need to reload.  Any ideas what is causing this?

[Alfred.DeFlaminis]

Hello @Anonymous,

I'd like to look into this for you, but I have a few questions.  Which version of 3ds Max are you using and which software is the FBX coming from?  Can you please describe your modifier stack in 3ds Max and what sorts of things are changing on the source model when you reloaded it?  Thank you very much for doing so.

Best Regards,

[Anonymous]

I am using 3ds 2016. The model is coming from Revit 2016. In 3ds, a lot of the materials are coming in wrong, as in, a wall in Revit with brick in the exterior and gypsum board on the interior is coming into 3ds as all brick. So I am adding an edit mesh modifier to walls and selecting faces and having to go through the model and grab the faces with the wrong material and change it to the right material. Then back in Revit, I have to add another wall somewhere. I don't change any existing walls. When I then reload that fbx export, all the materials I fixed in 3ds end up like that screenshot I sent.

[Alfred.DeFlaminis]

Hello @Anonymous,

I think what is happening here is that as you are adding detail to your mesh, the face numbers are changing.  So, because you have an "edit mesh" on the top of the stack, when the model gets reloaded the faces it was referencing aren't the same faces they once were, which is messing with your material assignments.  I did some testing on a teapot, and this material changing behavior occurred when I had an edit poly on the stack with material changes, and then I changed the number of faces on the original model and reloaded.

I don't know Revit, but FBX was remembering my material assignments from the scene it originated from.  So you really have a couple options for dealing with this issue.  1) Set your material ID's in Revit. or may try to 2) Link the Revit file instead of an FBX, which gives you control over individual objects.   Here are a few links with more information, though some of it may be redundant for you. 

It may make more sense to use the revit link instead of the FBX link.  If you don't mind me asking, what is the draw of FBX link vs. Revit link when coming from Revit?  At the end of the day all that you really need to do in Revit is make sure the right ID is applied, and then you can use a multi-subobject material and just drop it on the incoming models if the model has changed.  But using an Edit Mesh on top will basically confuse the face numbers/selections because the incoming geometry and face/vert count doesn't match the stack above it.  Does this make sense?  

Best Regards,

[Anonymous]

I have to use the FBX link method because of the size of the model I am working with.  With similar projects that I have done in the past, the file is too large for the Revit link method to handle.  Lots of times I have to break up the model into different parts by exporting an FBX from Revit with certain parts.  

That makes sense that the edit mesh stack causes the object to lose its material ID.  I don't seem to see any way to set material IDs in Revit.  I don't think it handles materials the same way that 3DS does in that way.

[Alfred.DeFlaminis]

Hello @Anonymous,

Ah ok, that makes sense.  I wonder if we could still link the FBX but use the Revit import types, illustrated below.  This might be worth a try.  My Revit knowledge is limited, but I think the key here is getting the material ID assignments in Revit, which according the this link here, does exist under the hood.

Best Regards,

[Alfred.DeFlaminis]

Hello @Anonymous,

I just wanted to follow up here, any progress on your issue?

Best Regards,

[Anonymous]

I have actually been using that Revit dialog with my FBX files.  I import the FBX and "Combine by Revit Category."  I am processing large models and like to bring in the objects grouped as walls/floors/roofs/etc.  And for what it's worth, I have been doing this same process for several years now.  It seems like some update in either Revit or 3DS 2016 has created this issue.  I don't have 3DS 2017 yet, so I haven't been able to test if this problem still occurs.

[Alfred.DeFlaminis]

Hello @Anonymous,

Understood, thank you for the update.  You'd mentioned you've been using this process for years, is there anything different?  Is it possible that in the past the objects had materials assigned in Revit that sort of cemented the Mat ID's but this time the Revit file has no materials when it comes to 3ds Max?  Any chance the export settings from Revit have different settings?

Best Regards,

[Alfred.DeFlaminis]

Hello @Anonymous,

I just wanted to follow up here, any progress on your issue?

Best Regards,

[Anonymous · Accepted solution]

Sorry I had gotten distracted.  I found a workaround.  It seems to fix the weird materials issue if I imported the objects based on the Revit Material, instead of category.  That means I had to export just walls from Revit and import that file into 3DS.  But now I can at least change the walls or add some in Revit, re-export the walls, and when I reload that link in 3DS, the materials stay correct.  Basically I have a separate 3DS scene for my walls that I can reload and export out.  

Thanks

[Alfred.DeFlaminis]

Hello @Anonymous,

Glad to hear it, I had a feeling that the "By Material" would help because it sets the material ids under the hood.  Thanks for the update!

Best Regards,