What about Non-Photorealistic Rendering (npr) in Sketchfab?


(Jmrudent) #1

I recently discovered that today, tendances go to stylized renders.
Half tones, outlines, flat shadows, textures, half frames animations…

Spiderman into the spider verse is a huge reference, and I see bunch of artists who want to imitate this style.
Zbrush has now NPR solutions which are stunning.
I see on Sketchfab a lot of techniques trying to fake some styles (bakes, weird post effects, painted textures, 2nd mesh for outline, … )

Is there any way to have a solution in the sketchfab editor, like a post-effect, or editable matcap, we could use to edit outlines, the shadows, put 2d textures (like half tones) in some areas, or other filters.

It could be a great way to stylize a high poly sculpt without texture for example.

Zbrush has a really cool list of filters i would love to see in SkFb :
http://docs.pixologic.com/user-guide/materials-lights-rendering/rendering/npr/npr-filters/


#2

Hello,

Thanks for your message. While we don’t support a lot of stylized shaders directly, there are many techniques to get things like that working on Sketchfab, as you’ve discovered (duplicate mesh + backface culling for a cartoon-like outline, shadeless mode, using emission to fake a shadeless look while still allowing reflections and other effects, heavy use of post-processing filters, etc.)

We also do allow uploading custom MatCaps, including per-material. Although, I guess it’s limited in that you can’t have a matcap on one material and regular channels on another in the same scene.

Supporting lots of different shaders would be very interesting, but also difficult to maintain. Are there any in particular that you think are widely used but currently impossible to achieve on Sketchfab?


(Shaderbytes) #3

Zbrush is of coarse doing all this offline. Sketchfab is a real time renderer. While some effects can be and have been done in real time others may be to costly to get working with an acceptable frame rate.

For example doing outlines mean doubling up the model. ( whether you do this manually , like is currently done on sketchfab , or in a shader - you never escape the need to double up the amount of polygons to be rendered ( perhaps not exactly double is computed though as some occlusion maybe factored in and the occluded pixels skipped )

Even this has issues in that split edges are not handled well. So additional performance heavy aspects need to be added to the shader to overcome these issues. ( unless you do the double up manually and avoid those errors manually - but defeats the point of your post - a programmatic solution )

But I agree “Spiderman into the spider verse” is a great example of stylized rendering. Just bare in mind it is rendered offline.


(Shaderbytes) #4

Its a great case study from an artistic point of view. While it would be great to just add some Post filter and it magically does everything for you , I think it is good to learn and understand what is required to make such artwork.

The thing to take away here is Firstly the detail has to be reduced dramatically , amount of color variations reduced as well, then the stylized aspects line half tones , outlines etc considered on top of that base logic. A thing to consider is dropping the notion of normal mapping on any surface as well , any such detail should have some simple lines in the diffuse to suggest the detailing etc.

hth


(Jmrudent) #5

I understand. What i’m saying, is that people are always cheating to have reccurent fx, or filters.
For example the ground shadow. People used to add a plane themselves, but now it’s a feature in the editor. Awesome move from Skfb.

Every nice features of the editor are there for realistic/pbr (DOF, SSS, local reflections…)

We see a lot of outlines. What if this trick was in the editor ?
We see a lot of baked light in the diffuses. What if a magic button baked “offline” the entire scene ?
We see a lot of stylized textures, what if we had fancy filters for our textures ?

I don’t know how the renderer works, but what if we could exploit the shadow pass, the z pass, the ao pass ?

image

We have Classic, Pbr and Matcap, I suggest a new “Cell shading” one, where we could play with new filters :

  • shadow color
  • shadow sharpness
  • flat shadings
  • color ramps
  • outlines : thickness/color (the 2nd mesh technique inside the editor or a edge detector)
  • add textures in AO, or shadow, or specular

For me the most important is the outline witch we see everywhere like the ground shadow.
But it fits in the npr tendance, witch for me needs features to play with in the editor


(Shaderbytes) #6

yeah it should be possible to do most of those , i mean you get such tools for purchase on the unity asset store. But obviously in unity you can write/edit shaders

Im looking at this tool for my game in unity :slight_smile:
https://assetstore.unity.com/packages/vfx/shaders/realtoon-65518

I fully understand , this style of toon rendering has become popular again so sketchfab should consider making a few new options in the editor to pull of this style with a few clicks :wink:

chat soon


(Deuschanz) #7

One thing that is definitely needed is a toon or cell shader imo. Go search around sketchfab and what do you normally find? Anime or cartoony looking models. And most of them dominate your searches.

So I think an outline or toon shader is a justifiable feature to consider.