Beam image via mirror object onto wall

[davorin]

Hello

Just downloaded the Octane demo for macOS 10.13.6 as I am on Nvidia GTX1060 (o;

I've searched in the past days for a render software which can do this setup:

A light source which casts a bitmap image or movie via a mirror object onto a wall..thus simulating sort of a beamer...
So far I only stumbled upon LuxCore render which does the job just perfect inside Blender, but as it requires bidir rendering no GPU acceleration is possible (though LuXCore uses all CPU even when rendering through GPU ;o).


Is this something that can be done in Octane without bidir rendering?

Attached the output of LuXxCore renderer inside Blender 2.79b.

[frankmci]

I'm not sure what you mean by "via a mirror" but, sure, Octane can use an image as a projection from a light source, acting like a film projector. There are quite a few discussions on the subject in the Otoy forums.

viewtopic.php?f=27&t=46016&p=231913&hil ... ge#p231913

These happen to be a C4D examples, but the same principles should apply, regardless of plugins or Octane Standalone.

https://www.youtube.com/watch?v=3IVCXIuHDeo

And another from Ahmet from a few years ago.

https://vimeo.com/83003488

Good luck!

[davorin]

Well setup is simple....

One lightsource at one side which beams a bitmap image....
on the other side a plane object with 100% reflection....
and last a matte objects where the reflection from the mirror plane is beamed to...

Don't have C4D on my Mac...only use Blender or a text editor like in the good old days of SunOS 4.1.3 and PRman or BMRT

But I definitively have a look at it...I'm impressed so far at the speed with a low end GTX1060...and tomorrow a GTX1080 Ti should arrive to play with

[davorin]

Hmm..this C4D example looks like a way to go...though there are several settings which just don't exist in the blender plugin... https://www.youtube.com/watch?v=3IVCXIuHDeo

I get something projected but makes no sense at all....

Guess I have to continue to use slower luxcore renderer...

[davorin]

Starting over again...set the emitting plane a little bigger so I can see the texture..

When I set the border mode of the texture to "wrap" the texture is around the same size as the plane and it emits light...

As soon I set the border mode to "black" the whole scene is dark...

[davorin]

No matter what I try..I never get anything that cast an image onto anything....

And I can't export it to test in standalone OctaneRender...


Also the option "Surface brightness" only shows effect in the material preview...but not in the render output...

[davorin]

Tried now a quick setup in standalone version though I never used...but seems to work on first try...
the mesh object is still too large though as the projected image is blurred...

Trying then to map all settings back to blender scene...

[davorin]

Works in the standalone version with path tracer...

Though after 5000 samples way worse looking than with LuxCore renderer

[davorin]

Can't get the image any better...just lots of ugly noise in rendering...

[davorin]

It just does not work with the same setup in blender as in the standalone version...

The preview is shown correctly with the projection...but just dark in the render output...

So what is different using the blender octane version compared to standalone?