3D Modeling information

[Madox58]

So your working on a new ship.
As you work,
faces keep flipping like fish out of water!
WTF?
Kit bashed or one off from scratch?
Here's a heads up for you.
It's all in the way the program you use works,
and the relationship of the parts in a single obj file.
I only use 3DS Max 9
so this post addresses 3DS Max only.
Other programs may or may not have the same results.
I noticed the faces flipping problem when I started kit bashing.
Granted, I was new to 3D model stuff so figured it was me.
Not so!
It's in the way each part is connected to each other.
If you delete a part of a given model,
some faces will flip.
You re-flip them and export.
But when you re-import them and do more work?
They flip again!
WTF?
Doing a total one off ship,
I finally figured this problem out.
And have the solution for 3DS Max users.
Other programs may or may not work the same.
So here's my proven fix for what I do.
While takeing apart a stock unit,
(Deleteing pieces)
I noted the faces flipping.
So I saved each part one at a time and studied the results.
I then started building from scratch, the Bathurst.
As I exported, then imported, I saw the same problem.
Faces that were correct were now flipped.
I re-flipped, exported, imported, still messed up!
I changed settings for export to group by object
instead of group by material.
That has solved the problem.
I've tested this with stock SH3 units
and it so far has solved this also.
BUT!
Anytime you delete parts of an existing file?
Things will flip!
You must then do a re-flip and export/import operation.
(Deep Exploration 5 is much more tolerant of the deletion of parts
with out this behaviour.)
This face flipping also happens as you detach parts.
Detaching parts is needed to follow the SH Engines Smoothing routine.
Look at the larger parts of any Ship in SH3 or SH4.
All the sharp corners use seperate parts.
But the Hull is one part.
That's because we want the Hull smoothed.
No sharp corners.
Building things from scratch, I detach parts or sides.
They will flip if not careful on export and import!
The main unit for the Bathurst has over 30 seperate parts so far.
Many are broken into seperate parts.
Those are then tested for the flipped faces
and tripled checked.
I keep all parts seperate until the final build.
Then I import each part and export as a whole.
Then import and export one more time.
This binds them as one.
All faces should be correct by this point.
Should I delete anything from this final build?
Faces flip!!

[Letum]

It reads like a poem.


Anyway...when you talk about "separate parts", do you mean elements in one object?

You know you can get good smoothing results in SH3 with out detaching things?
Just assign diffrent smoothing groups in max and make sure you export them.

[Madox58]

Yes, We could call them elements.

Say the Hull is one element,
the deck is another.
Now add all the other parts.
Each an element.

BUT!
We don't want some parts smoothed.
That's where detaching parts comes in.
The Bridge should have sharp edges.
Not smoothed.
We detach each side to keep corners crisp and very sharply defined.
Those are not new elements,
but can affect a face flip depending on how it's handled.

[Letum]

You can make unsmothed corners by assigning the two faces different smoothing groups.
The only issue is that SH3 does not recognize the unassigned group as unsmoothed so you must assign ALL faces a group.

[Madox58]

What are you useing to import and export from the dats?

[sergbuto]

Why would you use 'group by material' in the first place?

[Letum]

What are you useing to import and export from the dats?

Just max and s3d.
I can send an example if you wish.

[Anvart]

I used 3DS Max 9 and had no such problems ... :hmmm:
and + Sergey's question?