NPR in 2.8

Your only hope for NPR in 2.8 is Cycles!

Why? Because Blender Render, the NPR toolbox, is being removed in favor of another PBR toolbox, Eevee and there are no plans for NPR in it.

Yeah, let's just let that sink in for a moment.

##It gets worse!

Even the toon shader in Cycles can't be used effectivly with specularity!

...That means no more proper NPR toolbox in Blender... The compositor alone does not compensate - in fact, there is no compositor yet for Eevee and it doesn't hold up for Cycles (see FAQ).

# There is a solution!

## An NPR UberShader! With the claims: Eevee is to be Blender Render's replacement, Eevee will allow you to preview your Cycles shaders

It needs to at least be able to do what Blender Render could and have a toon shader for Cycles previews. This will help with a design for an Eevee toon shader and a very needed upgrade for the Cycles one!

Now, before anyone gets all

There is good reason we are making a proposal for such a shader.

Almost all of Blender's truly NPR tools are effectively being removed. We do understand why Blender Render is being removed (the recoding and update of Blender requires it's removal), but this does mean, again, that almost all the community's NPR tools are going into the can.

Just like everyone else, we're very excited about the release of Eevee and 2.8, especially with the promising render times (roughly 20x-60x faster than Blender Render). Plus, with the new Greace Pencil features, movies in the same vein as The Prince of Egypt, Treasure Planet, Blame and Tarzan become a lot easier to produce than ever and with talks of UPBGE being brought in to use Eevee, this is extremely promising for games too!

Wasili Novratidis and myself have been enabled to build something to this effect that works within the existing Diffuse BSDF shader (currently functional in Eevee).

Downloads, NodeMaps and more can be found here: ( pantherdynamics.yolasite.com/toon-shader.php )

The focus of this proposal will be on cell or toon shading because it is one of the most extreme forms of NPR - working back from that you can produce pretty much any style.

The toon shader functions easily in realtime in Blender Render so we know what we're asking for can certainly be incorporated and these shaders prove it too.

#Details

For NPR shading there has to be control over:

• Smoothness and Intensity of the diffuse
• Smoothness and Intensity of the specularity
• Reflection control away from specularity (such as mixing with a regular Glossy BSDF shader)
• Various specularity models (Blinn-Phong, Phong, Anisotropic)
• Brightness control of the Ambient Occlusion
• Brightness control of the Indirect Lighting
• Brightness control and type of Environment Lighting
• Material emission and shadelessness

Toon shader example with Eevee: Demonstrates functional environment light (through an emission shader), while receiving shadows accurately through the diffuse shader.

What this would come down to?

• An uber-shader equivalent for NPR
• Possibly a new light type

Why an uber-shader? An uber-shader is very similar to what we used to have in Blender Render. With the layout of the material system it had, it is very easy to transfer it's UI to nodes (see infographic). It would be extremely user-friendly and the results of each slider will be abundantly clear. You could say that it would be the NPR equivalent of the Principled BSDF shader - it's just principled in a different way.

Why so many controls? In order for NPR to exist, it needs to break a lot of physical rules. It goes a lot further than anime or looney tunes styles. There is a plethora of variation out there that includes comics (like Batman, Spider-man, etc.), anime (like Blame, BlueSteel, etc.), surrealism (can include impressionism, but includes anything that doesn't conform to set realism rules including light, color and textural effects - odd worlds like the intent with cosmos laundromat, abstract art as well as motion graphics are great examples where flex is needed), special effects (combining NPR elements with PBR ones like soft shading with hard toon shading) and of course you have games that can also alternate worlds and usually they are extremely stylized - meaning the rules have to be bent and far too. This would also open the door to more games and series, because it can seriously compliment the traditional animation methods - speeding up production dramatically and decreasing cost. You could say so many controls are needed to produce conscious imperfection.

Work done so far? Of course, to make this a reality, we can't expect the developers to simply just do everything for us. So we built with nodes what can actually produce what we want.

See the demos ( pantherdynamics.yolasite.com/toon-shader.php )

Unfortunately, they lack some small but important features nodes can't build.

These shaders still need:

• Access to the light sources to be able to have more than one light source at a time - can easily be added by duplicating and tracking additional light sources, but it's really not a good workflow. Way too many nodes.
• Massive speed up - nodes are not a fast medium to build shaders from the ground up with. If something is hard-coded, it will be much much faster.
• With input values, such as with group nodes, more flex would come into the shaders, because then even sharpness could be textured.
• All the specularity models built can be combined into a single node. The only reason they are separate is because there is no way a single setup will be fast enough (would probably be well over a hundred nodes with no auto switching for different light sources). The separate parts, as they are now, are as practical in speed as they're going to be atm.

Here is Moses from Exodus 7-12, KJV, rendered in Eevee with a three toned look:

Blender Render:

The difference is undeniable. Blender Render's NPR tools, including it's Freestyle outline system, far outweigh the ability of both Eevee (at this point) and Cycles (especially in speed).

See this post and video on the speed test: ( bibleanimations.yolasite.com/blog/foley-it-up ) (scroll down to Cycles Speed Testing Continues )

Blender Render is a fantastically fast tool for NPR. We're asking for similar shader features in Eevee and/or Cycles to be able to continue on in 2.8 and beyond.

I put together an infographic with what it might look like and how it could function:

Thank you for your time! (^^,) Be sure to check out Wasili's video as well and the FAQ section:

#FAQ's

There is a new NPR engine coming in the future

Not in 2.8 and certainly not anytime soon, nor is there any guarantee it will be coming at all. Already major features of 2.8 had to be postponed, Freestyle needs to be re-coded for realtime compatibility and there is yet to come a new compositor. A new engine takes extremely long to develop and as stated at the conferences, why build something entirely new when it can be incorporated into what we have already - Cycles and Eevee. That is what we took to heart and propose a solution.

Stick to an old build to keep Blender Render

Unfortunately, Blender Render is not the only tool for NPR and the Greace Pencil is sometimes included where 3D is lacking in flexibility. The new Greace Pencil features are not going to be added to 2.79.

Where is the demand?

The NPR community is actually not all that small and there is certainly demand for it. I have personally done a few toon shading tutorials for Cycles and by far, the first of those is the most popular with just over 40,000 views (it covers general proper toon shading for Cycles). With the node built Eevee NPR shaders, we also have over 2000 views. Note that I do not even have a big channel (like Andrew Price for example) and everyone has been told Eevee is PBR. I also specialize in doing tutorials for anime style effects and tricks in Blender Render (and more recently, Cycles too). Our Facebook community is always ablaze with discussions concerning NPR tools and that one group alone consists of over 6800 members. ( web.facebook.com/groups/303656779657432 )

A toon shader has also been a long requested feature for other engines, including Cry Engine, with very little reaction other than a general: "Shouldn't be hard to code yourself."

May 2016: ( reddit.com/r/cryengine/comments/4hdw7m/toon_shading_simillar_to_wind_waker_in_cryengine/ ) Jan 2017: ( answers.cryengine.com/questions/3815/is-celtoon-shading-possible.html )

One built around 2008 - never added to the official release (it's been 10 years - subsequent attempts also no longer exist - checked): ( cryengine.com/community_archive/viewtopic.php )

Stack Exchange question from Aug 2017: ( blender.stackexchange.com/questions/87752/cell-shading-can-eevee-do-well-with-npr-like-bi )

A recent query on BlenderArtists about 2.8: ( blenderartists.org/forum/showthread.php )

Development question on Right Click Select: ( blender.community/c/rightclickselect/Hvbbbc/in-the-npr-style-eevee-vs-blender-internal )

The demand is certainly there, it is simply never prioritized, because PBR enjoys, at this point in time, more popularity in both games, VFX and tutorials. One comment on the Eevee toon shader tutorial even showed the disheartened nature of NPR being so neglected: "Nice to see NPR getting at least some consideration" - CerealKiller

We don't know what to include or exclude for such a shader in a PBR environment.

That's what this proposal is for. It answers those questions and demonstrates that NPR can certainly exist within a PBR environment, provided that through specific tools (such as in this proposal), more fundamental control is given to the end user. Other examples of this being done are the Maneki tools with 3Delight and RenderMan with Lollipop's NPR shaders (even includes an edge detect shader). ( lollipopshaders.com/NPR/ ) ( maneki.sh/ )

Can't you just use what you've built?

No, because it is not a permanent solution. Nodes are not a fast way to work and we have already had to throw out some features because it's simply too slow. Additionally, no access to lights or light information is given so those are driver and empty based. This is a very functional, but only temporary solution, until something permanent can be added and since it isn't one built into blender, switching from the temporary solution is as easy as using the permanent one instead.

Can't you simply use Cycles instead of Blender Render?

No, because the Cycles toon shader has never been even close to the standard that Blender Render's was. It is PBR based and offers little to no control over the material (as stated above). So little in fact that in order for you to get proper specularity, you have to deliver the indirect glossy pass (this is a major problem with the denoiser and reflections) to remove the reflectivity from the toon shader (that really shouldn't be there in the first place)- this means no water, glass, mirrors, vehicles, metals, shiny plastic or anything that has any reflective surface. All the items listed at shader level are needed for it to work in reflections and for it to work with transparency and other shaders. Compositing is therefore clearly not a solution here.

See the reflections on suzanne in the mirror - technically impossible to remove in post. Has to be correct at shader level.

What about the compositor?

Like just demonstrated with the toon shader above, many factors prevent us from simply running to the compositor as a solution.

These are not limited to, but include:

• The Denoiser only denoises the final render, not passes. Therefore you need high sample counts to get a good consistent result.
• Material index and reflections do not go hand in hand. Indirect passes also do not see objects, therefore removing what needs to be removed is technically impossible at this point.
• Cycles is extremely slow as opposed to Blender Render. In fact, roughly 2.5x slower.

See this post and video: bibleanimations.yolasite.com/blog/foley-it-up

If it were the attitude of the community to tell people to just suck it up and deal with it, the current node built toon shaders wouldn't exist, the Greace Pencil would still only be an ugly black aliased line in 3D space and Cycles wouldn't exist either. We know the community cares, because we are part of it too and there is a clear demand for it.

Can't you just use OSL?

No, because OSL is simply like a scripted control table over what already exists. It does not allow you to create something that is fundamentally new. Even if it does so away from Blender, we have no access to light sources and we can't create new shader control points through it's API, therefore, we can't build this shader in OSL. It has also been suggested to add a GLSL API in the distant indetermined future, but this will probably, again, be a laid over system giving no means of adding something truly new and still no access to lights.

We truly need something that does not exist in Blender 2.8.

Does it have to be coded only by core developers?

Anyone can take this on if they wish. It is not exclusive to the code developers and their is no owner of ideas for Blender. Wasili and I agreed to license the shaders we built as CC0 to make sure that development on them was not halted by our limitations. I also added a section to the official documentation page that gives you permission to have at it and links to help you find the info you need to get it into Blender without a lot of hangups: pantherdynamics.yolasite.com/toon-shaders-documentation.php

Sources:

• Environment lighting with hemi lamps

( youtube.com/watch )

• GLSL Phong Specularity - WikiBooks

( en.wikibooks.org/wiki/GLSL_Programming/GLUT/Specular_Highlights )

• GLSL Brushed Metal - WikiBooks

( en.wikibooks.org/wiki/GLSL_Programming/Unity/Brushed_Metal )

• BlinnPhong Shading model - Wikipedia

( en.wikipedia.org/wiki/Blinn%E2%80%93Phong_shading_model )

• The Blinn Phong Normalization Zoo - The Tenth Planet

( thetenthplanet.de/archives/255 )

• H formula for Blinn Phong model - Review slide - Reflection Equations

( slideplayer.com/slide/9271897/28/images/6/Review:+Reflection+Equations.jpg )

Tutorials:

• Toon shading with soft shadows - Blender Render

( youtube.com/watch )

• Toon shading in Cycles

( youtube.com/watch )

• Advanced Toon Shading with Cycles

( youtube.com/watch )

• Blender 2.8 - Eevee toon shader tutorials

( youtube.com/watch )

• Eevee toon shader update v2

( youtube.com/watch )

Examples:

• Toon camp fire in Cycles

( youtube.com/watch )

• Eevee toon shader demos:
• Esther 6, KJV final scene

( youtube.com/watch )

• Feather demo

( youtube.com/watch )

• Suzanne Cannon demo (Blinn Sun Lamp)

( youtube.com/watch )

• Racetrack demo (Blinn Point Lamp)

( youtube.com/watch )

• Space Garage (Phong Point Lamp)

( youtube.com/watch )

• DayNight roll demo (Phong Sun Lamp)

( youtube.com/watch )

Additional links:

• Princeton Coherent Stylization, NPR and Jot
  1. Coherent Stylized Silhouettes

( youtube.com/watch ) 2) NPR Rendering using Jot ( youtube.com/watch ) 3) Jot ( jot.cs.princeton.edu/ )

• Blender NPR - Cycles and Eevee toon shader (Wasili's video on the matter)

( youtube.com/watch )

• Official download for the toon shaders

( pantherdynamics.yolasite.com/toon-shader.php )

• Documentation page

( pantherdynamics.yolasite.com/toon-shaders-documentation.php )

• BNPR Post explaining how they work and shows the features

( blendernpr.org/eevee-toon-shaders/ )

• Series of blog posts
  1. Happy new shaders

( pantherdynamics.yolasite.com/panther-dynamics-blog/happy-new-shaders ) 2) Blinn vs Phong ( pantherdynamics.yolasite.com/panther-dynamics-blog/blinn-vs-phong ) 3) Building a formula with nodes ( pantherdynamics.yolasite.com/panther-dynamics-blog/building-a-formula-with-nodes ) 4) Epilogue ( pantherdynamics.yolasite.com/panther-dynamics-blog/epilogue )

All images (C) Marius Oberholster