Object / World Space problem... [ShaderGraph Shader]

I'm trying to recreate MinionArts fake liquid Shader but by using ShaderGraph instead...
https://twitter.com/minionsart/status/986374665399685121

I'm currently stuck as I'm trying to get the liquid to stay "flat against gravity" while rotating the object... If I use World space on the Position node it works except the liquid volume is stuck on y=0, so it only works if it rotates around if it's on y=0. If I change the space to Object, the liquid stays with the model - but now the rotations no longer work...

So I need some way to give me the benefits of World Space but keep the liquid with the object regardless of where it is (somewhere that isn't y=0)

Shader:


Shader in use (with World Space on the Position node - flat with gravity but only works at y=0):


Shader in use (with Object Space on the Position node - now stays with the model but the rotations no longer work):

 

Did you solve this problem? Facing similar issue.

 

Subtract the object position from the world space position.

 

Where in the graph it should be placed?

Current behaviour:
https://imgur.com/a/sJdgNZG
when object is rotated:
https://imgur.com/a/AJuLDZU
All I want is to pulse cube on world Y axis not on object axix.

 

Position node set to World Space, piped into the A of a Subtract node. Object node's Position piped into the B of the subtract node. Use the output of the Subtract node everywhere you are currently using the current Position node's output.
https://docs.unity3d.com/Packages/com.unity.shadergraph@6.5/manual/Object-Node.html

 

Changed that graph as you said (hopefully)


but still same problem, object vertices are still moving around objects Y axis and not worlds Y axis:
https://imgur.com/LEMdRWD

 

Oh, I missed that you're directly manipulating the vertices. That's not going to work for a number of reasons. Not the least of which is you're passing in the object relative world position. Look at that gif you posted, notice you actually rotated the mesh 180 degrees!

To get what you have working a little more like what you want, try adding a Transform node at the end to transform from world to object using the Direction type.

Also you're using the XY value from the world position to drive your noise. You probably want to use XZ?

 

Thank you for help, I'll try to absorb what are you trying to tell me. But I don't think I'll get the wanted result anyway with particular graph.

All I want is to move vertices up and down on world Y axis independently on object rotation. Then I want to affect this movement based on Y world axis, so the lowest vertex on Y world (not object Y) axis doesn't move at all and the highest move the most.

Trying to figure out by myself a few days, but shader graph is too poorly documented (or I didn't found anything except almost empty unity documentation and a few Brackeys videos ).

 

Did exactly same graph as on the screenshot and it doesn't work at all, in scene mesh disappears and in shader graph is nothing on the main preview too.

I'am using HD pipeline renderer, could it be the problem?

 

Ahh ... yep. That's a key bit of information. The world position node is broken in the HDRP. There is no "world position" in the HDRP, but rather a camera relative position. So far the nodes are inconsistent about how to deal with that and some nodes assume actual world positions, and others are camera relative positions.

There's a thread somewhere on the Shader Graph forum on that topic which I think the official Unity response was something along the lines of "oh yeah, that doesn't work, not sure how to fix that, sorry".

 

Thank you for everything, you helped me a lot anyway.

 

Here's a SRP agnostic solution:

 

You are a genius!!!

I hope I finally get what I was trying to find out the whole time.

Few questions:

1. Why do we need to use remap and why are we using values (-0.25f, 0.25f)?
2. Output of that saturate node is 0 for the lowest vertex on axis (in this case Y) and 1 for the highest vertex on axis?

3. What saturate do in general as a node?

 

4. Trying to figure out what is going on before and after remap (using cube with pivot in center of bottom face not in object center and (0f, 1f) values as remap InMinMax):

 

Arbitrary decision, but the default sphere and box meshes have pivots at their center and are 1 unit tall, so unrotated & unscaled the min max is from -0.5 to 0.5 off of the pivot. Using -0.25 to 0.25 meant that the top vertices were being fully displaced, the bottom vertices aren't being displaced at all, even with some minor rotation, and there was still a small window of transition.

Yep.

Clamp between 0.0 and 1.0.
https://docs.microsoft.com/en-us/windows/desktop/direct3dhlsl/dx-graphics-hlsl-saturate

If it's at the bottom, then the first example would be 0.0 to 1.0 prior to the remap already, no? When you rotate that, the bottom vertex will be at -0.35, the "middle" two vertices will be at 0.35, and the top vertex will be at 1.05. That's not quite the perfectly balanced setup your examples show, but might be good enough. The bigger issue is really going to be scale. Since the above shader applies the object's scale then any kind of scaling of the mesh will mess all of this up, especially if your pivot is at the base.

You can work around that by doing the lerp in rotated, but unscaled world space. Like this:

 

Hello, is there any way you could send me what you did? Maybe your shader or even a part of your project using it? I'm facing issues having things to work properly (kind of a beginner with shaders...). In facts, when I apply the same shader as you did to my material, it instantly disappears. Nothing is rendered.

 

https://www.patreon.com/minionsart

Here's Joyce's Patreon, she is the original artist who inspired this thread. She has also now made a lot of her incredible shaders available in their ShaderGraph form (some are free, some are patreon bonus')...if you are still interested.

Her Twitter handle;
https://twitter.com/minionsart

 

Can you please explain why substracting this two position gives correct result in this case

 

Because you want a world space position relative to the object's position, not relative to the world origin. Subtracing the object position means "0,0,0" is now at the center of the object.

 

Thank you for your reply, but isn't moving the origin to the center of the object means I am getting object space position?

 

No. This is still world aligned and world scaled space, just object centered. An object space position would turn and scale with the object. For example the original post had the last image with the liquid surface going diagonal. That was using object space where the “up” was rotated with the object.

 

Oh now I got it. Thank you very much