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View Full Version : DDS formats are making me crazy

Archeopterix
07-15-2006, 05:41 AM
Help please! I'm going to need years of therapy after this one.

I have Photoshop CS, so the NVIDIA DDS plugins are included with my program.

However I'm having an awful time trying to figure out how to control them.

I mean for some reason I don't get the pop up save as menu each time so I can't choose from DTX1(no alpha) DTX3(alpha) and DTX5(normal map). And then when I do manage to get these going, they won't import into 3DS Max8, I get the error Invalid Image File Header..... :scream:

Max 8 comes with an included DDS plugin does it not?


I tried importing DDS files from a computer game (Oblivion) and those worked fine, so it's clearly something I'm doing wrong. :sad: I've searched for web-help and no one has seen these errors before.
AndrewRaZ
07-15-2006, 08:06 PM
well, first of all, the "usage" for each version of the compression isn't quite right. there isn't really a pre-set usage for each version, although some work better for certain tasks.

the biggest difference in these is the handling of the alpha channel. dxt1 has a 1 bit alpha channel, meaning it is either black or white, nothing in between. dxt3 has an explicit 4 bit alpha channel, which i think means that it has 16 shades that it can display. dxt5 has an interpolated alpha channel, which means that you get the full greyscale alpha.

The compression algorithms differ a little between the different versions, but in reality, i don't think any of them are really suitable for normal maps. most articles i've read, and engines i've dealt with, don't compress normal maps because of the artifacts the compression creates.

and finally, i've found that you tend to get much better results if you flatten your image before saving it as dds in photoshop. that may or may not help.

Gamasutra texture compression article (http://www.gamasutra.com/features/20051228/sherrod_01.shtml)
Unreal Developer Network explanation of texture specifications (http://udn.epicgames.com/Two/TextureSpecifications)
Another Gamasutra article dealing with textures and compression (http://www.gamasutra.com/features/20051123/linde_01.shtml)

found this one too: compares different compresion algorithms (http://udn.epicgames.com/Two/TextureComparison)
Archeopterix
07-15-2006, 10:45 PM
Hi, thanks, yes the images were flat. :)

I managed to get some older versions of the plugin, and I found that 6.1 worked, but no later versions than that. I really have no idea why that is.

I still, however, am unable to import them into 3D studio Max, I'm getting an I/O Image Error. I googled that, but came no closer to understanding what that meant, or how to resove the issue.
EricChadwick
07-18-2006, 05:41 PM
Hi, I have a newer version of Nvidia's DDS plugin, might help you.
http://boards.polycount.net/showflat.php?Cat=0&Number=115830&an=&page=0&vc=1

Also make sure you don't have Microsoft's Photoshop DDS plugin installed... that could be the source of all your problems.
Archeopterix
07-18-2006, 08:49 PM
Hi, I have a newer version of Nvidia's DDS plugin, might help you.
http://boards.polycount.net/showflat.php?Cat=0&Number=115830&an=&page=0&vc=1

Also make sure you don't have Microsoft's Photoshop DDS plugin installed... that could be the source of all your problems.

Yeah I did get the new one from Nvidia's site. Thanks tho :) 6.1 is working for me, it's exporting properly, and importing into Max, which the others wouldn't do. Wacky, that.
EricChadwick
07-18-2006, 09:07 PM
So it works in max just fine now? I thought you were getting an I/O error.
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