How to fix ST, Non-linear/planar mapping errors

[DaSquade 0]

Inspired by feersum.endjinn and his Section tutorial, i will try to provide a rough guideline in fixing ST errors, non-linear and non planar mapping errors.

Bear in mind, this is not official and i might be wrong on some parts. Also i'm bad at explaining, so feel free to correct or adjust.

First of all, O2 has provided us the 'check faces' option witch helps us moders to find any non optimized errors in brand new or old models. Some are nasty some are tollerated and unavoidable afaik.

So when you have your models in O2 after you are sure all needed merged points are connected (depending on style of import).

Now some say it is best to completly convert your model into tris (1 face-3 points) instead of working with polies (1 face-4 points) as in the end the engine will always have to work with a tris. But for editer and user i prefure to work with as less tris in my screen.

*You can convert your full model into tris by selecting your model and press /.

*You can convert your full model into polies by selecting your model and go to "Structure->Squarize (or Squarize all LODS).

Note: If you have an imported model, it will not convert some tris into poly as those will by non linear meaning one or more of the points making out the face is not aligned with the rest.

Again depending on your workpipe, sometimes you will not need to do this, sometimes it is a good thing to do the poly->tris->squarize.

Note: As this prosess involves making and deleting edges, this is very important regarding your sharp/smooth values as they depend on the existing or non exisiting edges. A new created tris edge will normally have a smooth value so most of the times it won't screw the overall values of a face.

Lets continue and run the 'check faces' option that can be found under Structure.

->This will add the 3 following named selections in your selection menu:

If you don't see any added named selections from the above, jump around and feeel happy. If not, continue...

Without going into detail of the errors itself (check wiki or forum for more info about that), lets split up the errors:

* Non-linear mapping:

Easy to fix: press the named selection (* Non-linear mapping) and press /. In normal cases that will fix the problem.

* Non-planar faces:

press the named selection (* Non-planar faces) and press /. In normal cases that will fix the problem.

Note: normally if you already did the above explained part about tris/poly you will normally don't have the two previous 'errors'. In the end these aren't big problems, it is more about how the engine will deal with them. When they aren't defined or cleaned out you let the engine deside what to do with the faces. This can turn out good but sometimes not (example: invisible faces under certain angles, deformed textures, bad lightning values, ...etc).

Next step are the nasty ones, bear in mind this is out of experience and not official...

* Cannot generate ST coordinates:

From what i know there are two kinds of ST errors or there are two ways you can encounter an ST error, but in bought examples they deal with bad mapping.

2 examples of ST errors are:

-Overlapping faces (mostly by bad defined polies where the engine will create a bad or crosssection edge when converting into tris).

-Very badely deformed and streched UV mapped parts.

In most cases these errors can only be fixed by taking your model (back) into a more advenced 3d program or if you can life and work with the O2 uv editor you can try to fix them there.

In some cases you can fix them up relativly simple by playing around with the following tips, but like said most of the times you can't and you will need to step back to the mapping:

-Work with one of the "ST coordinates error" face per time as the way you fix them depends on their individual needs.

-Select one of the faces you have an ST problem is and study them (be it in the wireview or bulldozer/render).

-If you can't noticed any deformation you might be able to fix it by converting the dual tris (depending on problem area) into a poly. Invert it (press W) and make them tris again and reverse them again. I was able to fix some ST errors this way, but like i wanted to point out the problem is sometimes not reversable.

->More will be added if i can think of some or additionally info is requested.

Hope this helps some and provide a better optimized model. In the end this is only one of the many steps an modeler needs to run through when he aims for making the best out of his work!

[CameronMcDonald 146]

Also note that standard BIS models have ST errors, namely near the eyes and the groin, however, when binarised these don't show up in the ArmA.rpt.

Great tute, Dasq!

[DaSquade 0]

Yeah forgot to mention. Afaik it is normal like in the eye case, i think (you can check with BIS face UV) the eye lid it already mapped for the moment the unit has a blinking eyelid, so then there is no stretching. But in current non static form it is in deformed statues...but wild guess. Same goes about the groin.

-> Like said, two types of ST errors that i know of. Guess texture deformation (in non flat case) can slip through the bin process..

Again wild guesses and no time to test here.

[earl 0]

ST coord errors (both causes, degenerated triangles and stretched mapping) are only a problem for drawing normal maps.  Such errors prevent the normal map from being displayed on that particular bad face.  I was told there is no performance problem if you leave ST coord errors in your model.  If you have no normal maps, there is no reason to worry about them at all.  If you have normal maps, then I guess you only have to worry if you see visual problems.

Both errors indicate poor modeling/mapping though, so I usually check new models during the mapping phase to make sure I don't have any problems or to correct them while I'm doing mapping anyway.

It's pretty crazy to try fixing some of the old OFP imports.

[scubaman3D 0]

No performance issues with the ST?

^thanks! I've been wondering that for forever.

[MehMan 0]

I'm not sure if there are no preformance issues with ST errors, I think somebody reported that it causes preformance issues on a dedi server. Anybody double checked this?

[earl 0]

Model errors causing performance issues on a dedicated server that isn't rendering anything?

[MehMan 0]

IIRC it's because it fills up the RPT. I'm not sure though, I didn't expirence this, but somebody made a post here.

[Panda-PL- 0]

IIRC it's because it fills up the RPT. I'm not sure though, I didn't expirence this, but somebody made a post here.

What is with this RPT cultism around here lately???

Try to understand what the rpt is telling you. In most cases it says "you suck at modelling" or "your UV maps could be done better" . But in 99% of cases aside from your model not being state-of-art professional pice of work there are no consequences, really.

[MehMan 0]

I'm having these wierd problems lately, O2 reports non linear mapping on a small piece which I later reuved to no effect and nonplanar faces which have been triangulized, to no effect.

Help?

EDIT:

Ignore this, I thought selections get updated when you press check faces again.