Best way to make part of a mesh transparent?

[Rasmus Hauschild]

Hi everyone!
I'm looking for a way to create a similar effect to this in Mario Odyssey: https://youtu.be/AIcEYLP4HW0?t=541
Basically, where part of a mesh becomes transparent when the player walks behind it. Any ideas on what would be the best way of achieving this?
Preferably if there was a way to use a second static mesh to block out what part of the original mesh should become transparent.

Any advice is greatly appreciated!

[presto423]

Are you talking about when Mario goes behind the water after traveling through the pipe?

[Rasmus Hauschild]

Are you talking about when Mario goes behind the water after traveling through the pipe?

Actually, I was thinking about the effect right at 9:05 in the video, where the octopus enters the hole in the wall, but I think it is pretty much the same effect as what you mentioned.

[presto423]

Oh, I see. The mesh it's inside of is darkened / made translucent in parts of it to display the inside of the mesh as the active nav area.

I'm not sure. There's Masked blend mode. It could be a transition based on the player entering a trigger volume, and the camera's distance from the mesh, to result in 0 opacity on parts of the mesh containing this material (or another way of identifying the parts to go invisible). So, apply this material to the areas of the mesh getting made invisible. There's also defining the areas of the mesh to become darkened, which could be a post process material that is applied to the camera during the time the player is inside / behind the mesh. It's a starting idea, not a full solution.

Nodes to use: SceneDepth, ComponentMask, DistanceBlend, Lerp, WorldPositionBehindTranslucency

[Rasmus Hauschild]

You've definitely given me some ideas to try out - thank you!