Incorrect calculation of vertex normals for appearance sliders with rigged meshes

[Beev Fallen]

did you ever notice this happens to your mesh body or head?

no matter the slider position, your 'parts' shaded identical.

on minimum or maximum slider position, you get the same shading of your nose or breasts or whatever other parts.

this is a major flaw (or bug?) in rigged mesh shading in Second Life.

if you're using Second Life NOT with a shadowless WL presets like CalWL, this affects your avatar for years.

you never get your unique face or body shape shaded right, the shading always looks like the default shape.

please consider spreading this information and click 'Watch' icon on a newly created JIRA on this link:

https://jira.secondlife.com/browse/BUG-228823

thank you.

Edited May 27, 2020 by Beev Fallen

[NiranV Dean]

As far as i can tell this is not an issue with shading itself, its more of an issue that the shading is baked into the object on export/upload.

On a similar topic its also the reason why taking parts of a body (for modification) and reuploading only that modified part produces light seams. The object which has been reduced to the modified parts only is shaded differently since it is now a different shaped object and its "ends" are located differently. The resulting different shading is then baked into the object and uploaded resulting in light seams when combined with the original "whole" object.

What i'm saying is, you need to upload the object without any shading (if that is even possible since its always shaded on export) and apply the shading post e.g via textures (diffuse, normal and spec).

I'm pretty sure that if the shading was updated dynamically whenever the mesh is transformed via shape sliders we'd end up with even more problems, especially more light seams, in fact we would probably have light seams on everything that isn't one complete solid mesh.

[Beev Fallen]

10 hours ago, NiranV Dean said:

As far as i can tell this is not an issue with shading itself, its more of an issue that the shading is baked into the object on export/upload.

On a similar topic its also the reason why taking parts of a body (for modification) and reuploading only that modified part produces light seams. The object which has been reduced to the modified parts only is shaded differently since it is now a different shaped object and its "ends" are located differently. The resulting different shading is then baked into the object and uploaded resulting in light seams when combined with the original "whole" object.

What i'm saying is, you need to upload the object without any shading (if that is even possible since its always shaded on export) and apply the shading post e.g via textures (diffuse, normal and spec).

I'm pretty sure that if the shading was updated dynamically whenever the mesh is transformed via shape sliders we'd end up with even more problems, especially more light seams, in fact we would probably have light seams on everything that isn't one complete solid mesh.

nothing is baked in the video i posted. the test asset is made by a skilled body rigger. check yourself, the asset box is here: http://maps.secondlife.com/secondlife/Hangars Liquides/32/224/128

upd:

[4:51 AM] xxxx:its very easy to calculate vertex normals on the fly
[4:51 AM] xxxx: by just averages
[4:51 AM] xxxx: every 3d modeling software does it in realtime as you model
[4:51 AM] xxxx: and so does the default avatar in second life

Edited May 29, 2020 by Beev Fallen

[NiranV Dean]

22 hours ago, Beev Fallen said:

nothing is baked in the video i posted. the test asset is made by a skilled body rigger. check yourself, the asset box is here: http://maps.secondlife.com/secondlife/Hangars Liquides/32/224/128

upd:

[4:51 AM] xxxx:its very easy to calculate vertex normals on the fly
[4:51 AM] xxxx: by just averages
[4:51 AM] xxxx: every 3d modeling software does it in realtime as you model
[4:51 AM] xxxx: and so does the default avatar in second life

Yea but note that the default linden mesh body was a super low poly whole-body mesh. Calculating vertex on that one was pretty fast, this might look entirely different with several highly complex avatars around that all have hundreds of rigged mesh pieces worn. I forsee this being implemented as realtime updates because its so cheap to do ending up with a massive performance loss around avatars.

[polysail]

Correct me if I'm wrong here ~ but ... uh... don't vertex normals HAVE to be recalculated under deformation?  Constantly? That's a substantial part of what a GPU does. ~ That's it's 'thing'  ~ otherwise nothing would animate ~ period.  No?   I think?

 

If I had to take a wild-flying guess as to what's happening here ~ is somehow slider deformation isn't getting fed to the lighting calc ~ Somehow?  I'm no rendering expert either ~ but this is definitely worth investigating further.