Another pet peeve - no inside faces on clothing

[ChinRey]

On 12/31/2022 at 7:22 PM, OptimoMaximo said:

And this is addressed to @Beq Januso

Beq is one of the exceptions to the rule of course.

 

On 12/31/2022 at 7:22 PM, OptimoMaximo said:

Plus, what Arton noted

Yes, and that is also a very good point. Mind you, I did not say that strict logic always is the best approach to a task. In fact with highly complex tasks, such as creating software for a whole virtual world or organizing your texture collection, you eventually have to take some shortcuts and implement some "fuzzy" solution to be able to do it at all.

Edited January 1, 2023 by ChinRey

[Beq Janus]

On 12/31/2022 at 6:22 PM, OptimoMaximo said:

A property like this makes more sense in a shader rather than a shape. The shader can simulate something at render time, which is lighter weight than generating the back faces from a geometry node: the former simulates on screen starting from the actual geometry, the latter should actively duplicate and flip the target geometry.

That is the point, for this to be done on the GPU means that those triangles that would previously have been culled earlier in the pipeline now have to pass all the way through. You cannot simply say "oh but its GPU" that is not how it works.

I don't disagree with Arton's point that there is darkness and light in all. Until I see otherwise my belief is that this path leads to more shadow than sunshine. In an environment where content quality control is nonexistent and creator skill and conscience is highlyt variable, the downside to this seems greater than the potential upside. I hope the creator community will prove me wrong.

[Beq Janus]

On 12/30/2022 at 10:27 PM, ChinRey said:

 

Also having double sided as a material property makes it more flexible, rather than having the entire mesh double sided, or not

Actually this is not true, though I guess you may be considering what is a "mesh" as different to what I consider a "mesh" to be. 

In the Viewer every material face is a separate mesh, thus an object composed of a single item (no links) and 6 materials is 6 separate meshes. By definition, making the material double-sided makes that entire mesh double-sided.

This is in contrast to have individual triangles replicated where necessary by a creator that is doing their job properly.

ETA: The Quote says it was @ChinRey but I think I quoted her quote of @arton Rotaru (sorry both)

Edited January 11, 2023 by Beq Janus

[ChinRey]

3 hours ago, Beq Janus said:

In the Viewer every material face is a separate mesh, thus an object composed of a single item (no links) and 6 materials is 6 separate meshes. By definition, making the material double-sided makes that entire mesh double-sided.

This is in contrast to have individual triangles replicated where necessary by a creator that is doing their job properly.

Yes but remember we're not talking about whether backfaces are good or bad in themselves right now but rather whether they should be defined as part of the geometry or the materials. I was actually going to post a similar comment to yours earlier but then Arton gave me second thoughts. Defining backfaces as part of the geometry is only likely to increase the number of redunant tris since creators then are more likely to add backfaces to entire meshes, not to separate faces.

The solution is of course to only use automatic backfaces when a substantial part of a submesh need them and do it the old way with duplicated flipped normal tris if it only applies to a small part of it but how likely is it that the average SL mesh maker will realise this?

But oh well, backfaces are coming to town whether we like it or not.

 

4 hours ago, Beq Janus said:

ETA: The Quote says it was @ChinRey but I think I quoted her quote of @arton Rotaru (sorry both)

You did but no problem as far as I'm concerned. Being credited for one of Arton's comments is only flattering.

Btw Beq. Since I have your attention, I have two Fs questions unrelated to this. Sending you a PM.

[OptimoMaximo]

On 1/11/2023 at 9:31 PM, Beq Janus said:

That is the point, for this to be done on the GPU means that those triangles that would previously have been culled earlier in the pipeline now have to pass all the way through. You cannot simply say "oh but its GPU" that is not how it works.

I don't disagree with Arton's point that there is darkness and light in all. Until I see otherwise my belief is that this path leads to more shadow than sunshine. In an environment where content quality control is nonexistent and creator skill and conscience is highlyt variable, the downside to this seems greater than the potential upside. I hope the creator community will prove me wrong.

I guess that passing any number of triangles to the gpu would work on its blackface feature. This means that whatever gets culled is not being sent, and the shader on the gpu renders backfaces of those that aren't culled. If the system is not organized like this, that's something that needs to be implemented, because it can be done and it's nothing new. I don't see the problem with keeping the culling mechanism and send the result to gpu to perform its operations. Unless, as usual, LL code has subpar limitation in this regard, which I can't be aware of.

[Beq Janus]

2 hours ago, OptimoMaximo said:

I guess that passing any number of triangles to the gpu would work on its blackface feature. This means that whatever gets culled is not being sent, and the shader on the gpu renders backfaces of those that aren't culled. If the system is not organized like this, that's something that needs to be implemented, because it can be done and it's nothing new. I don't see the problem with keeping the culling mechanism and send the result to gpu to perform its operations. Unless, as usual, LL code has subpar limitation in this regard, which I can't be aware of.

They cannot be culled efficiently, backface culling is simple, is the normal pointing away from the camera, yes, great nothing to do here. In some cases that may be done on CPU avoiding it at the earliest possible opportunity or in other on the GPU. With double-sided faces you have no such test, with rigged mesh we cannot rely on depth sorting ot come to our aid and with alpha blend we'd not even have that anyway, so overall it will result in more overdraw,  more time wasted, more unwanted load on the GPU.

It is entirely possible that there is something more cunning planned that will alleviate this; my fingers are crossed in anticipation.

As I have implied before, I don't disagree that there are cases where this feature has benefits, but as always we have chosen to add new footguns to the creators' arsenal and loaded them, without putting in place any gunlaws or guidelines on how they should be properly used. The end state will be an overall increase in time wasted due to poorly defined assets and a loss of scene performance that goes hand in hand with it, all for a rather niche feature.

Edited January 13, 2023 by Beq Janus