Hide part of model using alpha layer in texture only?

[mcnools 62]

I tried searching but couldn't find what I was looking for. I was wondering if it's possible to hide part of a model (a helmet in this case) only by editing the alpha layer in the texture somehow? (making the helmet completely transparent). I tried doing this, colouring the helmet completely black in the alpha layer, saving as .tga, opening in texview2 and saving it as .paa, however, the helmet in game just turns out dark grey/black instead of transparent. What am I missing here? if it's even possible that is.

(not exactly a modelling/O2-question, but it's model-related and I couldn't find a texture-forum?)

Edited November 2, 2011 by McNools

[PuFu 4591]

why don't you use hidden selection method? And is the diffuse map _ca. What is your rvmat?

Edited November 2, 2011 by PuFu

[mcnools 62]

Ah, the diffuse map is _co and not ca, could that be the problem? I'm experimenting a little with models and textures from the Czech soldiers from OA, for some personal use.

Edit: Changing it to _ca instead of _co didn't help, so I'm guessing it might be rvmat-related then? Or related to any of the other non-diffuse files? How does hidden selection work by the way, and is it useable even when you can't edit the model?

Edited November 2, 2011 by McNools

[PuFu 4591]

_CO doesn't have an alpha chnl. Either way there is no way you could hide models with alpha. and there is no way you can add hidden selections without actually knowing the selections and being able to edit the p3d.

[mcnools 62]

Argh, okay then! thanks for the info! :)

[Foxtrop 10]

Did you solve it? Try photoshop with .paa pluging and export it directly.

For some reason always I save a texture in .paa, it has as default the alpha channel, so I remove it by repainting it

[PuFu 4591]

DO NOT USE THE PAA PS PLUGIN! as it is borked

[frankyman 10]

since Arma 2 an _co map is able to work with an 1 bit Alpha Channel.

1Bit = black or white no grey or Smothing is supportet.

[Synide 0]

since Arma 2 an _co map is able to work with an 1 bit Alpha Channel.

1Bit = black or white no grey or Smothing is supportet.

yes, the _co type is a dxt1... and technically it can support 1bit alpha... but... you should never fall into the trap of using '_co' as a texture format that supports alpha in the context of this game engine because both TexView2 & pal2pace do not do a 'good' job of handling it when writing out the .paa. So, it's better if everyone believes that '_co' doesn't support 'alpha' - ok?

If you want to have TexView2 & pal2pace output a texture that supports transparency then tell those tools to process the image as such by giving your 32bit.tga a texture filename with '_ca.tga' or '_raw.tga' or '_1555.tga' or one of the other 'alpha' supporting formats mentioned in TexConvert.cfg as the suffix. This then will tell these tools to do a much better job of handling the alpha channel when they write out the .paa.

Did you solve it? Try photoshop with .paa pluging and export it directly.

For some reason always I save a texture in .paa, it has as default the alpha channel, so I remove it by repainting it

It's NOT a good idea to use keygety's .paa plugin. Why? Because when he wrote it he did not know of the exact swizzling that was needed to be done when writing out the .paa for ALL the different '_suffix' formats. It can write out a perfect .paa if you use no swizzling AND you've done all the proper swizzling yourself manually in Photoshop before you save out the .paa BUT people usually always forget todo this... So, it's much easier to tell people NOT to use it.

_CO doesn't have an alpha chnl. Either way there is no way you could hide models with alpha. and there is no way you can add hidden selections without actually knowing the selections and being able to edit the p3d.

You can 'hide' parts of a model with alpha transparency. But it's not a recommend method. Especially with existing .p3d's as many of the OA.p3d's (and later) specify all the textures through the use of .rvmat's and as these are embedded in the model it's an 'expensive' excercise to override them.

You can do up a new config for any given existing odol.p3d specifying hidden selections but only if the allocation of those selections exists currently in the odol.p3d. And, of course you need to know what those names are... that's why I released that little 'memrpt.exe' tool that tells you what they are, if they exist. If you come across an existing odol.p3d you'd like to enable hiddenselections on AND it currently doesn't have that setup AND the if the selections are fully defined throughout the various LoDs in the odol then all you need is the correct names. Run the tool and it'll what (if any) selection names are present in the Mem LoD. Hopefully, they will also be defined 'well' throughout the rest of the LoD's thus allowing you to create a new config entry for that model specifying the hiddenselections.

I tried searching but couldn't find what I was looking for. I was wondering if it's possible to hide part of a model (a helmet in this case) only by editing the alpha layer in the texture somehow? (making the helmet completely transparent). I tried doing this, colouring the helmet completely black in the alpha layer, saving as .tga, opening in texview2 and saving it as .paa, however, the helmet in game just turns out dark grey/black instead of transparent. What am I missing here? if it's even possible that is.

(not exactly a modelling/O2-question, but it's model-related and I couldn't find a texture-forum?)

As mentioned above... many (almost all) OA.p3d's and later primarily use .rvmat's to specify all the textures. And, as these are embedded in the odol.p3d you're not supposed to alter them. But, even if you went ahead and tried for you're own use... you should be aware that it requires you to get it absolutely perfect. Very time consuming and ultimately pretty pointless todo.

This doesn't mean you can't create your own model and use transpareny in textures to make subtle things not viewable. But, it's really a nasty way to do it. It's much better to use the whole hiddenselections mechanism - it's what it's for.

Cheers, Sy.

Edited November 5, 2011 by Synide

[max power 21]

yes, the _co type is a dxt1... and technically it can support 1bit alpha... but... you should never fall into the trap of using '_co' as a texture format that supports alpha in the context of this game engine because both TexView2 & pal2pace do not do a 'good' job of handling it when writing out the .paa. So, it's better if everyone believes that '_co' doesn't support 'alpha' - ok?

I have to disagree. I think it's better that everyone gets familiar with its quirks and develops techniques that minimizes the unwanted behaviour. For instance, for certain alpha on alpha problems, or for shadow-on-alpha problems, you must use a dxt_1 texture. The work around, if texview creates an unattractive alpha, is to create your own 1bit alpha before texture conversion. I think everyone who works with these tools should know their capabilities and limitaitons. The only reason it's 'better' if everyone believes that '_co doesn't support alpha' is if you lack the patience to explain the actual situation and choose instead to lie.

[frankyman 10]

texview2 makes perfekt _co.paa maps. Its the best way to get holes in Meshes witkout modeling the holes.

I use this technic for Tracks , holes and alpha Shadow Lods.

No Face Order, no Alpha Bug with smoke Effekts ...

Sorry for my bad English.

Im to old to learn it :blush:

[Synide 0]

If you want a 1-bit alpha diffuse use _1555.paa or _raw.paa.

argb1555 is analoguos to a dxt1 with 1-bit alpha. The only reason I mentioned it was because I have seen a small number of occurences when the 2 tools have stuffed up when writting out a _co.paa with 1-bit alpha but I haven't seen any occurences when they've stuffed up writing out a _1555.paa.

Cheers, Sy.