skin shader a la Alsurface pleaseeee

[jstrob]

For characters the best by farrrr is 2d displacement.. super crips.. less memory needed and faster .. though it depends wich resolution you set it at of course. but for now in max it dont support udim.. and i use udim like 4 udim of 8k on a head instead of 1 to get much more resolution to have super crisp define details.

Ok my god!!! at which resolution do you render and how much of the face do you zoom in?

[jstrob]

For characters the best by farrrr is 2d displacement.. super crips.. less memory needed and faster .. though it depends wich resolution you set it at of course. but for now in max it dont support udim.. and i use udim like 4 udim of 8k on a head instead of 1 to get much more resolution to have super crisp define details.

In max and zbrush you can always use many UV spaces without UDIM. You just have to move your packed UVs in relative mode to 0, 1, 2 or 3 in U direction and you can gat any number of maps that you want. so I don't understand the need for UDIM except if you use mari or nuke where it seems to depend on it. but zbrush and max don't need that.



then if you have many uv spaces in max and go to Zbrush using GoZ, paint with polypaint and the export with multimap, zbrsuh will create a map for each uv space.

[Bigguns]

thats what i do. call it multi uv tile if you want or udim.. all the same to me.. just the naming is specific for udim... but multi uv maps moved on other cadran then the 0,0 dobt work in vray 2d displacement.. but it does in maya.. figure it out.. meanwhile i have to do with the 3d displace wich is not enought precise for what i need...

[jstrob]

thats what i do. call it multi uv tile if you want or udim.. all the same to me.. just the naming is specific for udim... but multi uv maps moved on other cadran then the 0,0 dobt work in vray 2d displacement.. but it does in maya.. figure it out.. meanwhile i have to do with the 3d displace wich is not enought precise for what i need...

For me there's not a lot of difference between 2d and 3d displacement but 3d displacement renders 2 times faster with the same settings. to get crisper result you must always put the blur of your Vray HDRI texture to 0.01 instead of the default 1 (Vlado, why can't we put this to zero? and why is it at 1 by default BTW. I recently bought a camera without low pass filter and the pictures can be much crisper with it, and I don't get much moirée effect cause the sensor is so large (Sony A7IIR) I thinks it's kind of similar problem.)

Also I just did some test with one of my insect models and even if I am using 4 uv spaces, the 2d displacement is working in max (max 2016 and v-ray 3.40.02).

[vlado]

and why is it at 1 by default BTW.

Because it's a terribly bad idea if you are using tiled .tx or OpenEXR files and have 150 GB of textures... Instead of using the appropriate mip-map level, V-Ray will be forced to load everything in memory.

Best regards,
Vlado

[Bigguns]

last time I checked it was not working.. is it working now Vlado?

Jstrob : if you compare them with default value it's useless.. 2d dislpacmeent has a resolution parameter, put it like a 3k and up, you will get sharpness you can only dream in the 3d. and in the 3d displacement, if you lower the edge lenthg to get more details.. it becames dead slow and take ram like there is no tomorrow.. and ultimately, freeze you'r system

[jstrob]

I just did a test to make sure of it and what I found is that 2D mapping makes absolutely no difference if the blur is at 1 or 0.01, but with 3D mapping there is a huge difference. And in my tes I prefer the 3D displacement. And the good thing is that it's almost 2 times faster.

First this is 2D mapping with HDRI blur to 1. Render time was 24 minutes.


Second this is 2D mapping with HDRI blur to 0.01. Render time was 24 minutes and result was identical (there is a little region where the render was not finished, my mistake, also render time on stamp is not good cause I did a render region)


Third is 3D mapping with HDRI blur at 1. Render time was only 12 minutes, but this looks less crisp.


Finally, my preferred method: 3D mapping with HDRI blur at 0.01. Render time was 14 minutes and it looks a lot crisper than HDRI blur at 1. Looks also better than 2D mapping to me but there's not much difference in fact except the render time.

[jstrob]

last time I checked it was not working.. is it working now Vlado?

Jstrob : if you compare them with default value it's useless.. 2d dislpacmeent has a resolution parameter, put it like a 3k and up, you will get sharpness you can only dream in the 3d. and in the 3d displacement, if you lower the edge lenthg to get more details.. it becames dead slow and take ram like there is no tomorrow.. and ultimately, freeze you'r system

Ok I will try that.

[Bigguns]

and BTW I always put the blur to 0,01. Vlado, I noticed if I change the bump map in the alsurface to something else then the pyramidal ( I putted none ) in the bitmap it just don't render.. EDIT : I t don't render the bump, I don't see it, but the image is rendered ^^
And Jstrob, you model don't have super fine, mesoscopic details.. not so a good test to really compare. you need super fine, high frequency's to see well the difference, like on skin, it's a huge difference. It create a much better realistic break down of the reflections lobes.

[Bigguns]

Hi Vlado, a problem I see with you'r autobump is this :

in a small render it don't show much.. and the bigger the render the bigger it shows.. should be constant! that's why if I render let's say a 1500 pixels, the reflection look more powerfull, since less breakdown.. (wich is wrong ) and if I render in Big , it's looking MUCH better ... that's the problem I found a while ago with the bump.. I don't know if it's in the nature of the bump .. or if it's a Vray problem.. but it's why I never use bump.. look not constant depending the size you render the image.. but when I use 2d displacement, it's perfect from small render to big render, always the same, the reflection is not getting stronger or less depending of the size, the breakdown is always occuring wich bring consistency.. and it's very important!!

[vlado]

you'r autobump is this

It's not a problem with "our" bump; it's a general problem with bump mapping and bitmaps in any renderer.

Best regards,
Vlado

[jstrob]

Wow! bigguns you're so right!

Look at that: at 4K with 2D mapping and HDRI blur was at 1. render time : 23 minutes!
You can see a big difference in the eyes!





Maybe the note in the doc should be changed:
Note: In previous V-Ray versions, there was a great difference between the performance of the two mapping methods, with 2D mapping (landscape) being faster than 3D mapping in many cases. With the introduction of dynamic geometry handling in V-Ray 1.45.xx, 3D displacement has become a lot faster with similar or better results when compared with 2D displacement. For large displaced surfaces like oceans or mountains the 2D mapping (landscape) method might work better, but this method keeps the displacement map in a precompiled state in memory, so large displacement maps can take up a lot of memory. It might be more efficient to use 3D mapping with very large maps since it can recycle the memory used for the displaced geometry.

Note: corrected the wrong picture and wrong render time at first.

Youcan better compare here:

[jstrob]

Since it increases render time so much I would use 3D for everything except the eyes, where there is such a huge difference in this case.

[jstrob]

Because it's a terribly bad idea if you are using tiled .tx or OpenEXR files and have 150 GB of textures... Instead of using the appropriate mip-map level, V-Ray will be forced to load everything in memory.

Best regards,
Vlado

I'm not sure to understand that one. In the max doc about bitmap coordinates I see this:
Blur
Affects the sharpness or blurriness of the map based on its distance from the view. The farther away the map is, the greater the blurring. The Blur value blurs maps in world space. Blur is primarily used to avoid aliasing.

But you are telling me it's more memory intensive to not blur the images than to blur them?

[jstrob]

You can see how my UVs are spanning over 3 uv spaces here.