DXT why?

[sonic]

I have read at several places that you can convert your aircraft to dxt using image tool,  my question is why what whould you gain by doing this.

[igorski]

You gain (or rather loose)  file size, and loading time. DXT is a compression, so files are smaller, and load quicker and may exhibit higher frame rates. However, you also loose quality with the compression, so I usually stick to 32Bit (except for AI use where small files are most uselful)

[Merlin66]

Just to add to igorski's reply. The compression of texture files using Dxtbmp is significant, a 1.4Mb texture file can reduce to 650Kb. Really makes a difference when uploading!
I haven't found a whole lot of quality difference when textures are compressed to DXT.

[igorski]

Thanks for adding that, i never checked the differences, I have sometimes noticed a slight difference, and you have to be more careful when repainting becuase if you repeatedly edit / compress / decompress / edit / compress..... then your files get really mucked up!

[racartron]

Converting large bmp's can have a significant impact on usability for those on old machines -- like me  :)

Whereas one of those PMDG behemoths with an 80mb+ texture file is a bear to handle as delivered, I can reduce it to around 15mb or so and have a very enjoyable time flying it about.

Also with an older machine -- and graphics card, the visual difference is not even noticeable.

Having said that, with a more powerful machine, there is no need for the conversion.

[Moach]

i have discovered that you will lose a great deal of image quality if you don't resize your texture image to a power of 2... (512x512, 1024x512, etc) because DXTBMP or any other converter will have to do that for you, and it doesn't resize very well...

so always use powers of 2 for image sizes... that will keep images crisp even with compression...

c ya

Moach

[Merlin66]

That's because MS simulators 2002/4 and CFS2 can only read textures which are, as you say to the power of 2.

[Hagar]

That's because MS simulators 2002/4 and CFS2 can only read textures which are, as you say to the power of 2.

Going by what it says in FSDS2 Help I don't think this is always the case.

Just to add to igorski's reply. The compression of texture files using Dxtbmp is significant, a 1.4Mb texture file can reduce to 650Kb. Really makes a difference when uploading!

I think you will find that Extended BMP formats don't make much difference to the zipped file size. Compressed formats cannot be compressed much further, if at all, by zipping them up. Try zipping a JPEG. With some careful thought over texture sizes & formats the size of the average download could be considerably reduced.

For designers, planning the textures properly could reduce it further. I've seen many aircraft that use one texture for each part. This leads to a large number of textures, usually all hi-res & big files, when they could probably be grouped together on far less. The default textures are good examples of how it can be done economically. Some parts do not need large hi-res textures at all.

[Merlin66]

You're correct. I meant to say texture files can be rectangular ie 256 x 1024, 512 x 1024 etc.

I hadn't compared the final zip size of the typical texture file set between PSP and DXT format. I find a 5.6 Mb DXT set zips to 1.34 Mb, and a similar PSP set of file zips to 1.7 Mb. Interesting!