3ds file in Vray rendering got problem.....please help....

[Kwaikeong]

Kindly assist urgent case, recently too many same issue. 3ds file download from website when rendering by Vray got problem, others party rendering no issue.Anybody know about it is very very appreciate, please advise....Thanks! Please refer attached files.

[Kwaikeong]

this is file................... please advise

[fixeighted]

Convert the model to an editable poly.
Select polygon sub-object and select one of the faces that is flipped - look at the smoothing groups tab and note which smoothing group it is, then press 'select by SG' and check the same number and press OK.
This will select all those polys that are e.g. smoothing group 4 and they will all be flipped. Delete them.
Repeat this for all the polys that are flipped/coplanar or just plain wrong.
Finally select all the verts and weld them.
Won't take very long at all

[^Lele^]

Try raising Secondary ray bias to 0.001, from 0.0. (here)
It won't fix the model, but may fix the issue you're having with coplanar faces.

[fixeighted]

I tried that but it didn't work here unfortunately....until just now, when I tried it again and it did work. LOL.
Ah well, it at least made me find the technique, which cleaned the model properly, so I'm happy about that, as it was
something I hadn't previously used to fix models

[^Lele^]

Oh, the model will stay borked.
Alas, it'll render fine.

[Kwaikeong]

Convert the model to an editable poly.
Select polygon sub-object and select one of the faces that is flipped - look at the smoothing groups tab and note which smoothing group it is, then press 'select by SG' and check the same number and press OK.
This will select all those polys that are e.g. smoothing group 4 and they will all be flipped. Delete them.
Repeat this for all the polys that are flipped/coplanar or just plain wrong.
Finally select all the verts and weld them.
Won't take very long at all

Thank you for your kind explanation, I'm CAD user, not familiar 3ds max. So please refer attached files, it that you mean?

[Kwaikeong]

Try raising Secondary ray bias to 0.001, from 0.0. (here)
It won't fix the model, but may fix the issue you're having with coplanar faces.

Thank you for your reply, its got a little bit improvement but not perfect.

[fixeighted]

Sorry I am a little unwell so will post instructions in a couple of days unless someone else can

[fixeighted]

Ok, so if you haven't already figured this out, here is an update.

You need to convert to editable poly, which is simple enough.
To select the flipped face you need to be in 'sub object polygon' mode, not element.
You can tell if the face is flipped becasue it will be a darker red colour.
When you have found a flipped single face you then take a look to see which face id it has, which you can see in the 'Polygon Material id' tab
Then you simply open up that smoothing group tab and uncheck all of the numbers 'except' that face id. This will select all those flipped faces that are mat id 1, for example.
Delete these faces. You need to delete all those duplicate and flipped faces so you can weld the vertices.
Then just repeat for the rest and you will end up with no flipped faces, meaning that you can then weld all the vertices.

So to recap:

Convert to poly
Select single flipped face
Note its face id
Select by smoothing group id
Delete
Repeat
Weld verts

Smile