Cool Watercolor material with Eevee

Learn how to make your 3D mod­els look like water­col­or paint­ings with the ever use­ful shad­er-to-rgb node. If you pre­fer text tuto­ri­als, you can read the text ver­sion below.

The trick behind this water­col­or mate­r­i­al is to make it look like the objects are paint­ed on a piece of paper rather than an object in a 3D space. So the first step is to add a prop­er paper back­ground. Let’s hop into the wold editor.

World and settings

You can down­load the paper tex­ture here. We want it to always look the same, so objects look paint­ed on top of it. To get that effect let’s add a tex­ture coor­di­nate node and plug in the win­dow coor­di­nates. You can also use a map­ping node to move it around and repo­si­tion it. Finally I’m going to desat­u­rate it a bit and fid­dle with the con­trast using the curves node.

Now, we don’t want the paper mess­ing around with our light­ing. So we need to dis­able it for every­thing except the cam­era. We’ll use the old light path trick for this. Mix the paper tex­ture using the Is Camera Ray out­put with pure black. Now we can have one col­or for the light­ing and anoth­er for what the
cam­era sees.

We’ll use this tex­ture again when we make the objects mate­ri­als so let’s put it a node­group. Don’t for­get to throw some lights around your object so you can see their effect on the material!

Watercolor Material

Alright, mate­r­i­al time. Let’s add a new one and get rid of the prin­ci­pled shad­er. We are going to work this the same way we would do a water­col­or paint­ing: from light to dark. That means we let the paper show
through the light areas and cov­er the shad­ows and edges to sug­gest the form. And to do this we will be mix­ing things on top of the paper tex­ture using multiply.

Bring back the paper node we made before, and plug it into an emis­sion shad­er. Check it out: since the tex­tures in the mate­r­i­al and world are in sync we can’t see the mod­el any­more. Now let’s get start­ed with the edges. Add a lay­er weight node and low­er the blend to about 0.2.

We have to dis­tort this to make it look like paint. We’ll have to make a vec­tor that we can plug into the nor­mal sock­et of the lay­er weight that will look more like water­col­or. Add three noise nodes (one for each axis), a com­bine vec­tor node and tex­ture coor­di­nates. Plug every­thing togeth­er and the result of the com­bine vec­tor in the lay­er weight. Play around with the nois­es, you want to bring up the dis­tor­tion set­ting but not too much. Otherwise it gets too messy.

With these done, we need to get the shape of the object back. So let’s bring a geom­e­try node and a vec­tor math node and com­bine them with our painter­ly normals.

It’s also use­ful to con­trol the inten­si­ty of this effect. So drop some math nodes for each noise and set them to mul­ti­ply. Then add a val­ue node to con­trol the amount to mul­ti­ply. I’ve found that 0.7 looks good enough.

Back to the lay­er weight node. We’ll add a col­or­ramp to con­trol it, set it to bspline to make it smooth. Now the trick to get a water­col­or effect is to make the tran­si­tion areas between col­ors go zig zag between dark and bright so the tran­si­tions are dark. I got this trick from Hadyn Lander’s water­col­or uni­ty shad­er.

Let’s add anoth­er col­or­ramp set to constant to add hard­er edges. We can mix these two using a math node set to multiply.

There’s one more thing left to do here. I think it looks bet­ter when water­col­or paint seems to flow and around. We can use the win­dow coor­di­nates to get that effect. Add them with a Vector Math node the same way we did before.

Alright, let’s get the light­ing infor­ma­tion now. Bring back the prin­ci­pled shad­er and plug the painter­ly nor­mals in there. Add a shader-to-rgb node so we can con­vert the shad­er result into an image and plug it into a colorramp.

Now here’s the trick to get that water­col­or look.

Just like before, we want to jump between dark and light. This time we’ll have more col­ors stop, and packed tighter. You might have to zoom in real close for this. It also might be dif­fer­ent depend­ing on the light­ing in your scene.

Mix all these togeth­er using the mixRGB node set to (you guessed it) multiply.

Adding color

Time to add some col­or to bring this effect togeth­er. Add anoth­er colorramp in the prin­ci­pled shad­er area. Set it to bspline to make it smooth. Pick some col­ors suit­able for your mod­el and try to play with some hue vari­a­tion besides val­ue. These are the col­ors I used for the rose: #9B3E72, #D5A781 and white

Let’s add a final colorramp for the edges, again using bspline. This one needs to be a bit more sub­tle than before so the hard edges don’t stand out too much. These are the col­ors I used: #FFC1D2 and white

Hope you enjoyed this tut. Did you make some­thing cool? Let me know in the comments!