Distributing Procedurals with Arnold Scatter Object on Surface

[eddi_fuhrmann]

Hello.

I am trying to distribute some procedurals via an arnold scatter object on a landscape. I managed to have them look all in the same direction but they won´t stick to the ground. instead they hang in the air and i don´t know how to bring them to their position. thanks in advance and happy christmas 🙂

PS. Tried it with the normal tree instead of the procedural and they distribute evenly on the surface....any ideas?

pss. nevermind...they keep stucking in the mesh, too..Has some one and idea?

[madsd]

Upon export to ass, make sure that the trees are not offset from the world positions ground, so they hoover. We often see drifting when the pivot of objects sits below the objects, essentially baking in the offset.
This could be 1 explaination.

Verify by making a box that stands on the flat viewport ground and export and bring in to your scatter.

[eddi_fuhrmann]

he thanks for the answer but i am not really sure what you mean. do i have to reset the psr of the objects so they sit on the same spot. sorry for the dumb question but i am lacking a bit of the c4d basics here...

[madsd]

Im not using the application, so would have to look up the correct terms.
However, your main focus in practial is that you need to make sure that if you rotate the tree around in your viewport, that the rotation point sits at the very bottom of the tree, not 10cm up. If it sits somewhere else things will drift out of place.

[peter.horvath6V6K3]

The scatter tool sets the pivot or anchor point of the object to the surface point. Use the Axis Modification tool in Cinema 4D to set the pivot to the bottom of the tree. Here's a quick video showing how to do it: https://www.youtube.com/watch?v=yna5KhVHFXU

[eddi_fuhrmann]

ah thank you for the help. this makes sense of course. i will have a look into it. thanks and greetings

[eddi_fuhrmann]

okay i tried it and it workes so far...but i have still aproblem when i displace the mesh that i get the same problem again...the objects stuck in the mesh and don´t appear on the surface...

[peter.horvath6V6K3]

Right, depending on the displacement it could be an issue, since the pivot is currently a fix point on the original surface. Not sure I can do much about it now. I wonder if this is solved in other tools.

[madsd]

If he is using render time displacement, things will offset. Dont you have a way to inject this offset at render time in this host? Else this would perhaps be a solution, wondering if a small operator noodle could do it for him.

[peter.horvath6V6K3]

Scattering happens in export time at the moment, any automation or operator magic would be tricky I think.

You could try playing with the Position offset under the Orientation tab. You can use a shader (e.g. a vertex map) to control the offset based on the surface UVs.

[eddi_fuhrmann]

he, thanks for the answers...i think i will try the version with playing with the offset in the scatter settings...thank you so far!

[eddi_fuhrmann]

i have an other question conserning displacement, so i don´t have to open a new topic every time...i am having issues to figure out the best workflow iwth it...do you use the displacement in the shader with a texture or via the arnold tag or can you use a combination of both?

i am getting mixed results like a lot of those texture glichtes on displaced planes etc.

[peter.horvath6V6K3]

Not sure what you mean. Displacement is defined in the Arnold Material by connecting a displacement or image shader to the Arnold Displacement output. Then in the Arnold tag you can specify some parameters per object, such as the height, padding or autobump. They apply on the displacement defined by the shader.

[eddi_fuhrmann]

ah thank you for clearing that up. i thought you can change the apply with the displacement in the shader and also in the arnold tag. do you think it makes sense, for example, to displace a basic plane with a displacer and displace it afterwards again with the nornal displacement of the shader...got mixed results there,too. i don´t know if it´s too much in the end

[peter.horvath6V6K3]

Well, that's a double displacement, so you basically displace the output of the Displacer in Arnold, which is an already displaced shape.

You can enable subdivision to add more details. Check out the documentation: https://docs.arnoldrenderer.com/display/A5AFCUG/Displacement+shaders

[eddi_fuhrmann]

i am really desperate at the moment and can´t get the displacement working properly...some parts are completly flat and others are oddly displaced...

is it possible that i upload the szene file and you take a look into it?

[peter.horvath6V6K3]

Sure, please do.

[eddi_fuhrmann]

ok here is the wetransfer link...maybe you can take a look...thanks for the help!

https://we.tl/t-4o3dhnRwfV

[eddi_fuhrmann]

ok i think i figured it out. my texture was 3X3m and was distributed on a plane thats was way to big for the texture. i used on a 3X3 plane and it worked prefectly..if i want to use a bigger plane (lets say 6X6) do i have to put the scale u and v to 2 or does it not work that way..for 9X9 to 3 and so on...thanks for the help.

[eddi_fuhrmann]

ok i think i figured it out. my texture was 3X3m and was distributed on a plane thats was way to big for the texture. i used on a 3X3 plane and it worked prefectly..if i want to use a bigger plane (lets say 6X6) do i have to put the scale u and v to 2 or does it not work that way..for 9X9 to 3 and so on...thanks for the help.

ps. and if i change the uv settings for the colour i have to change them also in the texture for the displacement right?