Difference DXT3 & 888-Bmp's?
- Thread starter MrReset
- Start date
Mick
SOH-CM-2024
Ignoring the technical differences, the practical differences are resolution, which translates to on-screen clarity, file size, and stability of image quality.
"888" files are 32-bit images with extremely high resolution, and they display crystal clear on screen. But the file sizes are large, and slower computers might load them slowly enough that the loading time is perceptible; when you go to spot view, you might see the model untextured for a second or two before the textures load.
The big difference is in the stability of the image quality. Open any DXT file and look at it closely. (Sometimes you don't have to look very close at all.) You'll see a lot of corruption in places where there's any kind of detail, like panel lines, insignia, etc. You can paint a perfect texture, and as soon as you convert it to DXT format it becomes corrupted. Each time you open and close the file the corruption becomes worse. All but the slightest corruption will be visible on the plane in the sim.
I always work in 32-bit, keep and release my files in that format. If someone's computer can't handle them, they can easily convert their own copies to DXT with DXTbmp or ImageTool.
I just wish I'd realized how badly DXT files get corrupted back when I first started painting models!
"888" files are 32-bit images with extremely high resolution, and they display crystal clear on screen. But the file sizes are large, and slower computers might load them slowly enough that the loading time is perceptible; when you go to spot view, you might see the model untextured for a second or two before the textures load.
The big difference is in the stability of the image quality. Open any DXT file and look at it closely. (Sometimes you don't have to look very close at all.) You'll see a lot of corruption in places where there's any kind of detail, like panel lines, insignia, etc. You can paint a perfect texture, and as soon as you convert it to DXT format it becomes corrupted. Each time you open and close the file the corruption becomes worse. All but the slightest corruption will be visible on the plane in the sim.
I always work in 32-bit, keep and release my files in that format. If someone's computer can't handle them, they can easily convert their own copies to DXT with DXTbmp or ImageTool.
I just wish I'd realized how badly DXT files get corrupted back when I first started painting models!
Wild Bill Kelso
Charter Member 2011
I agree to Mick's words completely.
One more remark to the file size:
A 1024x1024px texture file in DXT3 compression has a size of about 1 MB, the same file in 32bit uncompressed amounts to 4 MB. Imagine an average aircraft consisting of four or five of this full-size texture files (fuselage, wings etc...), and you can tell the difference of the data masses your system has to handle.
This might be a good point pro dxt3 compression - but on the other hand, dxt3 creates these ugly artefacts and blurries already mentioned, especially on tiny details.
These are my Fat Albert textures for the PAD C-130J in DXT3:
Note the panel lines and the insignia.
Here's the same in 32Bit uncompressed:
They aren't razor-sharp either, for the whole fuselage texture consits of a 1024px file, but you can tell the difference.
I think Bob May of PAD made a good compromise:
The textures of the C-130J package are DXT3 compressions, to keep the whole download size to a reasonable amount, but he also offers the 32Bit textures as a seperate download for those who like to take a closer look...
Cheers,
Markus.
One more remark to the file size:
A 1024x1024px texture file in DXT3 compression has a size of about 1 MB, the same file in 32bit uncompressed amounts to 4 MB. Imagine an average aircraft consisting of four or five of this full-size texture files (fuselage, wings etc...), and you can tell the difference of the data masses your system has to handle.
This might be a good point pro dxt3 compression - but on the other hand, dxt3 creates these ugly artefacts and blurries already mentioned, especially on tiny details.
These are my Fat Albert textures for the PAD C-130J in DXT3:
Note the panel lines and the insignia.
Here's the same in 32Bit uncompressed:
They aren't razor-sharp either, for the whole fuselage texture consits of a 1024px file, but you can tell the difference.
I think Bob May of PAD made a good compromise:
The textures of the C-130J package are DXT3 compressions, to keep the whole download size to a reasonable amount, but he also offers the 32Bit textures as a seperate download for those who like to take a closer look...
Cheers,
Markus.
Wing_Z
Charter Member 2011
That's a good comparison, Markus.
I mentioned in a previous post that I tend to resize to DXT3 as a matter of course.
That isn't strictly true; some high-poly models can take a close-in zoom, and like your KBT Orion paint, can withstand really close scrutiny.
Most FS9 models, though, can only survive scrutiny to a zoom that frames the entire aircraft.
I test this by looking at the engine nacelles - if you can zoom in to fill the frame with an engine - and it still looks round - then you are looking at an exceptional model (and a resource-hungry one too!) and 32-bit might be more appropriate.
But most of the time, with most models, at the further viewing distance I don't actually notice too much difference.
So I guess Bob May has a good solution - offer both and let the viewer decide!
I mentioned in a previous post that I tend to resize to DXT3 as a matter of course.
That isn't strictly true; some high-poly models can take a close-in zoom, and like your KBT Orion paint, can withstand really close scrutiny.
Most FS9 models, though, can only survive scrutiny to a zoom that frames the entire aircraft.
I test this by looking at the engine nacelles - if you can zoom in to fill the frame with an engine - and it still looks round - then you are looking at an exceptional model (and a resource-hungry one too!) and 32-bit might be more appropriate.
But most of the time, with most models, at the further viewing distance I don't actually notice too much difference.
So I guess Bob May has a good solution - offer both and let the viewer decide!
Mick
SOH-CM-2024
Remember, too, that for great looks, only the external textures need to be in hi-res 32-bit format. The others can be in DXT-3 if they need an alpha channel, and otherwise 256-colors.
256-color external textures are deceiving; they look great in your image program, but they get fuzzy on the plane in the sim; they don't get corrupted, but there's just not a lot of resolution there. But if you really need a low-resource paint job, 256-colors can't be beat.
256-color external textures are deceiving; they look great in your image program, but they get fuzzy on the plane in the sim; they don't get corrupted, but there's just not a lot of resolution there. But if you really need a low-resource paint job, 256-colors can't be beat.