Model rendering weird issue

Hello guys,

I have strange issue while opening my latest model:

Everything is fine during 3d editing and few minutes after saving any changes. Then the model becomes partially transparent, even with two sided faces. Some of the faces gets visible and disappear at certain camera angle. Anyone knows what is going on?

Thanks for any help :slight_smile:

I tried to eliminate the problem of transparent faces by saving and checking the model after each change in edit mode. I noticed that the error only appeared when I used two textures in one material: diffuse and opacity (even png with alpha was not displayed well). Eventually, the problem disappeared when I split the model into two parts - solid and transparent. The first material has a color map only, the second is a simple, one-color transparency. The effect is satisfactory, but there is one more issue that I want to ask out of curiosity. After a few minutes of saving, the colors on the model change slightly. Is the texture compressed in any way?

do you use “shadeless shading”? just wondering why in a flat light model PBR.

This is happening in both lit and shadeless shading, classic and pbr renderer.

1 Like

Hello, we are investigating the issue.

Hi @biegnoncy,

We identified the issue and it’s caused by our conversion from PNG to JPG, which is run to optimize textures download in the viewer. When you upload a texture in the editor (or with a model), our servers generate an optimized version of it at different resolutions to be used in the viewer.

For small resolutions ( <= 512x512) the JPG quality parameter used is currently 95, which works most of the time but not in this case. The resulting JPG palette has slighly different colors and the diff is noticeable since each pixel is spread across big areas in the model.

Using a quality setting of 100 seems to do the job but we need to investigate to see if we could update the rules for this specific usecase.

We 'll keep you in touch if anything is done regarding this issue

3 Likes

Thank you very much! This is very useful information. I will remember to save textures as JPG in maximum quality if similar probem with PNG occurs again.

Unfortunately it will not fix the issue as our servers will always optimize your texture with quality 95.
The only workaround to avoid this inconsistency between Editor and Viewer would be to generate your texture with the same setting (95) but still it’s not guaranteed to work every time and it’s just moving the color issue from Sketchfab to earlier in your pipeline.

3 Likes

Oh, ok, I get it now. I’ll try it out when uploading next model. Thanks! :slight_smile: