Image compression issues


(Mrchlblng) #43

Thanks for this feedback @RBR! It is still not perfect but much better indeed.

I did not test that as actually generating an optimized png instead of a jpeg (as done currently on your model) did not lead to detail being washed out. I'll have to dig a bit to understand why the sRGB to linear/linear to sRGB conversion would be so destructive for jpeg. My quick guess would be that maybe the 'empty' pixels in your map could be the reason but that will need investigation.

(Stephomi) #44

From @james screenshots, we output a linear normalmap when we should not.
Pixels on the compressed texture are normalized in lin space: || rgb/255 * 2.0 - 1.0 || ~= 1.0
Original texture is normalized in srgb space: || srgbToLinear(rgb/255) * 2.0 - 1.0 || ~= 1.0


(Mrchlblng) #45

@RBR, @stephomi is kind of right. The issue is that we were having an implicit colorspace conversion happening only with JPEGs. It's interesting that increasing the JPEG quality was somehow also decreasing the effect.
A fix is on its way that will allow you to keep your initial sRGB map. We'll still have to improve the final quality to better preserve details.

(Mrchlblng) #46

@RBR the colorspace fix should be live now. We'll improve the compression quality in the coming weeks.

(Rbr) #47

Hmm does this only apply to new uploads? Because just going into edit and saving back out doesn't seem to fix it.

(Mrchlblng) #48

@RBR saving your materials is enough to trigger textures optimization (provided you actually made an edit in you materials, which is a new behavior).
And we actually had another silly case (sRGB vs srgb...) issue that hopefully has just been fixed.

(Ironbelly) #49

Certainly looking forward to improvements in texture quality.. These compression artifacts are marring what would otherwise be nice crisp normals frowning

You can see it in action here, yuck

(Stephomi) #50

Did you select "HD" quality in the viewer?
It looks like your screen are in SD.

By the way there's a small bug on our side, so instead of displaying LD/SD/HD, your model should only display LD/HD, (and in that case HD would be the default choice).
It should be fixed soon.

(Ironbelly) #51

Just posting up some other interesting issues we're seeing that appear to be coming from normal map compression on a weapon model we have in the works(7d9ca6b24eef49c88b429d00f49622dd). You can see all of these lines on the surface particularly when being hit by light

Difference In quality in 3d editing view and client view
(Headsethoncho) #52

Not sure if this thread is still active but I'm getting horrible compression on my normals like the sword above with no option to change LD/SD/HD in 3D settings or the viewer. Here is the model:

Mateba MTR-8
by Nicolas Riley
on Sketchfab

This is the look I'm trying to achieve from Painter

And here's a preview of what the sketchfab viewer is giving me

I've uploaded and re-uploaded this gun a dozen times with different settings, size maps, configurations, etc. to no avail, sometimes it even looks worse. Really confused as to why it omits so much of my normal map and compresses the rest.

(Delicious) #53

Having similar problems here. Switching from Normal Map to Bump Map makes the blurriness go away, but also changes the surface texture, obviously. Interesting that changing from one to the other would make a difference...


(Delicious) #54

Having related problems here: I am exporting from Substance Painter 2.0 directly to Sketchfab.

Compression is visible in the reflections. Interestingly, switching from Normal Map to Bump Map eliminates the noise completely.

(Mrchlblng) #55

@headsethoncho, @delicious,

thanks for your reports. We're aware that we still have issues with some normal maps texture compression.
We've been working on improving this but it's actually a difficult problem and we've no good solution yet. We even discussed converting normals to bumps but it doesn't look like the good solution (from our standpoint) and we'll probably have to use "in house" compression to keep assets size small while maintaining great quality.
We'll keep you posted on progress made on the subject!

(Bogdansuprun) #56

so any news about nm compression issues?

(Mrchlblng) #57

@bogdansuprun we unfortunately did not fix the normal map compression issue yet. We are still collecting models with issues. We will likely use a not "browser native" compression format so this requires thorough testing and stats aggregation (to make sure we are still mobile friendly) and might not be released in the very short term.

(Bogdansuprun) #58

it's pity. because marmoset toolbag (same issue) and sketcfab only this 2 ways to show 3d art portfolio, compressed NM just spoiling impression, now I thinking about publish or not...
As quick solving problem I can advice to you 2 version of NM, keep current compression and everything will be fine with mobile and other version is for pc/mac - GPU type detection decide what version will load. It's can be temporary while you are researching compression stuff.

(Stephomi) #59

@bogdansuprun The main reason why we compress texture is for download size, not really performance.
In any case, we are not using native GPU compression because the quality is not enough (on the supported format by webgl).
By "browser native", we mean the browser not the GPU.

So if we want to improve the compression, we have to use a format that is not supported by the browser nor the GPU, thus the decompression can take time (since it'd be done in javascript).

That being said, we still think it's worth it to do it for normal map, but we are currently not working on it, as we have other priority task in our roadmap.

For now you can add "?imageCompression=0" to load the original textures (but you can't save this settings).

(Bogdansuprun) #60

I see. Thanks for being in touch. I hope sketchfab will be good place where artists can show their next-gen high quaility 3d art.
"?imageCompression=0" - it's cool! I'll try use this in embed code.

(Bogdansuprun) #61

"?imageCompression=0" Is it stops working?? few days ago everything was good (embed and links), but now NM corrupted ((

(Stephomi) #62

All url options are now in snake case, so it's "image_compression=0".