Cell Shading in Unreal Engine 4

AzzaMat · May 2016

So I was messing around with creating art styles for my next game and ended up getting caught up in making a cell shader :P

Image: https://2.bp.blogspot.com/-fd8n36K1EpE/VzxMEq05jLI/AAAAAAAAEN0/DTT4Klvw-z84WwVhQIs839MehbVD7c-bwCLcB/s1600/CellShade.gif

So far I have
Textures supported

Diffuse
Normal
Spec Colour
Spec Strength
Spec transparency
Lighting Banding

Other

One Directional light or point light
Skylight/ambient light control
Post process to control shadows
Sobel Edge (courtesy of Allar's awesome little freebie)

Once its finished I plan on doing a tutorial but first, I would love to know what you want out of this kind of system, what controls/functionality would you like to have?

AzzaMat · May 2016

Name WindwakerTestpngViews 0Size 3888 KB

Making windwaker shading is pretty easy :P

sub · May 2016

Wow! Very cool! Really looking forward to your tutorial! Hope you release it soon
Is this just a material or did you change some code?

Here are some suggestions (don't know if those things are possible to achieve):
-setting number of steps and possibility to to control the color of every step
-being able to control what the shadowed parts look like via texture
-mix cel shading and normal shading for a smooth transition

Oniram · May 2016

What is the split of control over this between the material and the post process? Can you pump in your own gradient profile to control the shading per asset, or is it driven entirely by the diffuse? Is there a flag to check this for certain assets only, or does it default to everything? How do you determine light priority, and what happens if an object is lit by more than 1 directional light. Looking forward to seeing how this progresses.

AzzaMat · May 2016

Thanks guys, I will be releasing the tutorial soon

in the post process version, the material just holds the diffuse (rough must be set to 1) and the Post Process handles the lighting. The material only version doesn't have a Post Process.
The band control is a texture so it can be any colour and as many bands as you like

@SUB I will look into adding texture control to the shadow elements

@Oniram The post process handles lights really well but the material version will be limited in the number of lights. I am currently planning on splitting materials by creating an interior and exterior material. Interior looks for the nearest point light while exterior finds the directional.
The biggest problem at the moment is that the material only version doesn't shadow properly.