topic Re: 3ds MAX/Revit link geometry lighting issue in 3ds Max Forum

3ds MAX/Revit link geometry lighting issue

paulmonsef — Sat, 05 Aug 2017 14:50:26 GMT

This happened to me in 2017 as well, when linking a model from Revit certain faces would not cast shadows properly. the work around was to assign an Edit Poly modifier then things seemed to work fine.

started using 2018 this week and it appears we have the same problem and I've tried the Edit Poly Modifier with no luck.

Any thoughts?

Re: 3ds MAX/Revit link geometry lighting issue

Chri688m — Tue, 08 Aug 2017 06:59:55 GMT

Have you tried exporting the model as fbx or obj instead of having them linked?

Best regards

Re: 3ds MAX/Revit link geometry lighting issue

Alfred.DeFlaminis — Wed, 13 Sep 2017 23:46:09 GMT

Hello @paulmonsef,

First, I'd like to apologize that you experienced such a long delay before you got a reply here. I realize this thread is old, but I'd like to help find an answer for you. Are you still having this issue?

If so, you might take a look at shadow bias and make sure that the objects haven't been scaled down or up a large amount which could lead to XForm problems and may cause shadow issues. Would it be possible to share this file with me? If privacy is necessary due to NDA reasons, I can create a private folder for you. I am happy to do so if you would like.

Best Regards,

Re: 3ds MAX/Revit link geometry lighting issue

Alfred.DeFlaminis — Thu, 14 Sep 2017 23:10:05 GMT

Hello @paulmonsef,

I just wanted to follow up here, any thoughts on my previous post? Thanks for the update!

Best Regards,

Re: 3ds MAX/Revit link geometry lighting issue

paulmonsef — Sat, 16 Sep 2017 14:06:42 GMT

Thanks for the reply.

I have been working with Adesk support. Phone Calls, Emails, TeamViewer sessions. no one really knows why this is happening, but it was logged as an issue. For now, I am importing FBX files.

For your reference, the issue is logged as: MAXX-25154.

Re: 3ds MAX/Revit link geometry lighting issue

Alfred.DeFlaminis — Mon, 18 Sep 2017 17:29:20 GMT

Thank you for the lead @paulmonsef, I appreciate it. I checked out that defect in the tracker... hmm. I do see a note listed which states that using the system unit of Feet in Max before linking the files will resolve the issue when it comes to UV's, but there are no notes at all about lighting. It's worth trying though.

If you'd like I can try to take a look at the scene file and find a workaround (if possible). I could create a private folder for you if you'd like to maintain secrecy. Would you be interested in that?

Best Regards,

Re: 3ds MAX/Revit link geometry lighting issue

imigas434 — Wed, 15 Nov 2017 13:19:47 GMT

I deal with the same issue - linked RVT geometry often acts weird, black spots appears or shading is wrong.

As a workaround I use modifiers 'Edit Poly' (clearing smoothing groups), 'Edit Normals' (reseting normals) or even both at the same time.

It seems that either Revit or 3ds has a problem with transfered polygons and their normals.

Also, I tried to import rvt file into second rvt file (mockup house into site), mirror linked house geometry (so I had two mirrored instances) and then import 'site file' into 3ds. I used 'Combine by Revit Material' as always.

Results:

Pic 1. Render of imported RVT geometry, no 3ds modifiers.

Pic 2. Render with 'Edit normals' modifier. Still black spots visible on lower parts.

Pic 3. Render with both modifiers applied.

Looks good but it is not a solution.

Am I doing something wrong on any stage of this process? Or is something wrong with linking?

Re: 3ds MAX/Revit link geometry lighting issue

brentscannell — Wed, 15 Nov 2017 16:00:53 GMT

Thanks for those pictures @imigas434!

I'm from the product team, responsible for Revit workflows. Can you guys answer a few of the following questions to help me narrow down what's going on?

1)Is this only happening with File-link workflows? Does it manifest itself with a direct import

2)Is this happening specifically with FBX exports from Revit, or with file-linked .rvt files (or depending on the answer to question 1, imported .rvt files) ?

Re: 3ds MAX/Revit link geometry lighting issue

paulmonsef — Wed, 15 Nov 2017 16:12:52 GMT

1) Not as much as importing/linking an FBX file. That has other issues. Direct import is not really an option in the long run.

2) I see It mainly in linked rvt files. FBX links appear to work correctly, accept they tend to inherit an scaling issue.

See Case ID: 13263959 and Case ID: 13259759

Re: 3ds MAX/Revit link geometry lighting issue

Alfred.DeFlaminis — Wed, 15 Nov 2017 19:14:45 GMT

Hello @imigas434,

Thank you for the informative post. It does look like smoothing groups are being altered during the link process based on your images. I checked the tracker and I do see two entries about Revit normals on import. I didn't realize the lighting issue was linked to normals, it's sometimes difficult to get a scene to investigate. I have added your post as a link in the tracker about this issue.

One of the notes indicates that this may be a side effect of combining objects based on materials. I wonder if not combining materials would work in the short term. Would you mind trying that for me, or is it possible to share a simple scene with this issue? I don't know Revit well enough to test it myself. Thanks! If not, no problem and I have a added a link to your post in the tracker.

Best Regards,

Re: 3ds MAX/Revit link geometry lighting issue

imigas434 — Wed, 15 Nov 2017 22:05:19 GMT

@brentscannell

1. I will try to import this specific scene and will let you know what is going on.

2. I always preferred to use the fastest method of updating model in 3ds by direct rvt linking, so I don't have much information about FBX situation, but I will try this as well.

For your information, some observation I've made so far, maybe sth will be useful:

1. Black spots seems to be mostly connected with smoothing groups. Inverted shadows - probably with normals (some kind of backfacing issue?).

2. Edit Poly with smooth clearing seems to repair also inverted shadows (at least in this case above, as like the edit poly reseted normals as well).

3. Those instances of linked geometry shown in the pictures above with lighting/shading issue were broken in renders as long as they stayed linked geometry in Revit file. When I changed them to revit groups (simply by the Revit function link->group) and updated link in 3ds, the houses' faces in render suddenly were lighten properly (that's mysterious one..)

4. As far as I remember, the black spots (smoothing groups) usually appeared on surfaces close to different surfaces - in example: on wall finish with 1cm thick plaster layer and isolation behind. 1cm is rather close, maybe the improper smoothing let 3ds think these faces intersect or something.. ?

5. So far I've encountered black spots on both 2017 and 2018 versions, on couple different devices.

@Alfred.DeFlaminis

I'm gonna try this for you soon. However I believe combining by material is extremely useful and fast method of further development and it would be great if we could rely on it.

Re: 3ds MAX/Revit link geometry lighting issue

Alfred.DeFlaminis — Wed, 15 Nov 2017 22:47:20 GMT

I totally agree @imigas434. I realize how important that is because I've seen what a scene can look like without it. If it does resolve the issue at least it's a temporary workaround and maybe a Maxscript could instance the materials. The other benefit is that if that does seem to resolve it then I can confirm the note in the tracker and it'll help the devs to know where to tackle this. Thanks so much!

Best Regards,

Re: 3ds MAX/Revit link geometry lighting issue

imigas434 — Thu, 21 Dec 2017 20:46:20 GMT

@Alfred.DeFlaminis

@brentscannell

I had a chance to try FBX linking and as for now it seems that while linking FBX there is no problem with black shadows. I didn't have to make any modifications to get proper result using vray materials.

Tried again RVT linking and the problem appeared again (it was a clean max file with entirely new project).

Sorry for horrible quality, but hope you get what's the problem..

So.. I can use FBX, but I have to export it from Revit every time I want to synchronize + I cannot choose revit view (which is an advantage, it lets me filter elements I want to show in 3ds while linking). The question is how to make RVT linking proper and painless.

Re: 3ds MAX/Revit link geometry lighting issue

brentscannell — Thu, 21 Dec 2017 20:55:51 GMT

Saw this recently in another thread that turned out to be overlapping faces in those areas, could that be the case here? Could you attach that scene you posted a screenshot of?

Re: 3ds MAX/Revit link geometry lighting issue

imigas434 — Tue, 02 Jan 2018 23:03:17 GMT

I don't think this can be overlapping faces, unless some kind of smoothing options make them overlapped.

In this particular example window model has glass extrusion, about 0,8cm thickness.

Is it possible that it's too close for 3ds and presents those two faces as overlapped? I hope it's not..

As I wrote above, this effect disappears after Edit poly/normal modifications.

@brentscannell, can you give me the link to the thread you have mentioned?

I will do some tests on smaller model, not entire house, and then attach the file.

Re: 3ds MAX/Revit link geometry lighting issue

imigas434 — Wed, 03 Jan 2018 00:21:44 GMT

Some more interesting images with fast renders:

(I rendered with crop in the left and right side to show the difference according to the captions)

Re: 3ds MAX/Revit link geometry lighting issue

imigas434 — Fri, 23 Feb 2018 17:14:49 GMT

I let myself refresh the topic as I would really like to find people who also had such experience and may know something about it...

Re: 3ds MAX/Revit link geometry lighting issue

Anonymous — Mon, 12 Mar 2018 10:09:30 GMT

I hope that 3ds max 2019 will fix it.

Re: 3ds MAX/Revit link geometry lighting issue

Anonymous — Thu, 05 Apr 2018 09:37:46 GMT

Sorry for my English. The problem occurs even in the starting revit file. Please solve this problem. (revit 2018, 3ds max 2018/2019)

Re: 3ds MAX/Revit link geometry lighting issue

imigas434 — Fri, 20 Apr 2018 18:42:41 GMT

@Anonymouswrote:
I hope that 3ds max 2019 will fix it.

Well... 2019 did not fix it.