Mix texture and projection mapping [RESOLVED]

[dotcommer]

Having an issue here. I'm trying to create an optical illusion by having a camera projecting a texture (in this example the text "2014") onto other objects. When you perfectly line up another camera, you'll see the text.

I'm having problems with the projection map though. As you can see from the screenshot, the projection is hitting both the cylinder and cube, but the cylinder should be blocking most of the text from the cube. In this view you can see that the text is showing through on the cube, as though the two objects are being calculated separately (and in fact the text also shows up on the back side of both the cylinder and cube as well). Whats going on here? Am I doing something wrong?

[aoktar]

check my image, how i setted the position as global coordinates and rotated 90degree on X

[dotcommer]

Using your settings doesn't fix the issue. Try setting your projection camera to looking straight on at the cylinder with the cube larger and behind it. Now pull out from that camera and orbit around it to look behind the cylinder, and you'll see what I'm talking about. I think there is an issue with the projection camera feature. It looks like its calculating both objects separately and projecting the texture onto each normal in the projection camera's line of sight.

[aoktar]

No, it's working well as should be. It's normal to see that's stretched from different angles.

[dotcommer]

Hmm, let me try explaining a different way:

Imagine you line up two objects one in front of the other. The one behind is a bit larger than the one in front. Now I take a spray can, and I spray the objects dead-on. The majority of the spray paint would end up on the first object, with some blowing past and landing on the second object. If you were to then look behind the first object, you would see a halo, or outline, of the spray paint on the second object from where the first object was blocking it.

This is how projection mapping should also work, and at the moment, this is not working in Octane. I've attached my project file for you to see. Look around the cylinder, and the cube. Notice the text is showing up on the back sides of the objects.

[aoktar]

Sorry but i think that you scrample up concept of projections. Last example which you give, that's for projection of some textures by a light source. But this is only a mapping type. This does some matrix calculation which is similar to projecting a image. This is suitable to do camera mapping. I hope that we could agree on this. I think that you should do some post work to get the effect as you wish.

[dotcommer]

Ok you're right. I just tried to recreated what I was describing using just C4D shaders, but I'm getting the same result. I guess what I'm going for then is a projection like from a light as you say. Is there a way to do that in Octane?

[aoktar]

thanks. Check this scene

[dotcommer]

Hi Ahmet, thank you for the projector scene. Very useful techniques! It really is like a projector. Thank you for showing me.

However, I decided to keep messing with the idea in my mind of what I felt was a projection. I know I've done it before in C4D, but couldn't remember, so I just went back and messed around a bit and finally got it to work. I guess you would call this more of perspective texture sticking. I've attached my scene file so you can see what I'm talking about. Its different from your projection from a light source in that the texture is stuck to the objects, and does not act like a light (and thus won't be affected by other light sources). Essentially this is applying a texture and constraining it to selections on multiple objects, a similar technique I forgot I used for one of my tutorials for sticking a UV map to a shattering object to render out a UV texture pass for post-3D retexturing in After Effects.

Take a look and let me know what you think. Thank you for your patience and working with me on this issue!

[Murd0ck]

Hey there,

simple question: How u turned off the tiling?
When i try to add a Logo or sth it repeats so often it can.
Dont need it instant, just thought it fits to the topic.