Is there a possibility to visualize the cycles ray paths (in the 3D viewport)?

It would enable to get an impression of the field of view of multiple cameras when having reflecting and non-reflecting objects in the scene (geometrical optics simulation).

  • $\begingroup$ Just to clarify, you want the "field of view" to be seen like "show cone" option works for spot-lights, or the actual trace of the bounces like lines coming from the camera and bouncing all over? Also you are speaking of visualizing it in the opengl/3dview or in a render? $\endgroup$ Mar 9, 2016 at 14:29
  • $\begingroup$ I see now 3d viewport in the title, anyway I'm not aware of anything already developed in either case. For just the field of view, or better "view frustum", you can scale the camera as much as you want without affecting what is "seen" $\endgroup$ Mar 9, 2016 at 14:36
  • $\begingroup$ Exactly, I want to visualize the field of view, plus I would like to incorporate also the depth of focus. Kind of simulating multiple real cameras with a couple of mirrors and non-reflecting objects within the fields of view. One limitation of using the pinhole camera in the 3d viewport is that it can be scaled, but it doesn't get reflected on mirrors. $\endgroup$
    – Wydolor
    Mar 9, 2016 at 14:58
  • $\begingroup$ mirrors? pinhole camera? Am I missing something in blender? depth of field can already be seen if you enable limits under display (in the camera tab) and below there are an entire set of option under "depth of field" and you can pick an object as a reference or manually set the distance and aperture, But maybe I'm missing what you are asking, and maybe other can reply on this $\endgroup$ Mar 9, 2016 at 15:53
  • $\begingroup$ When the camera gets scaled you can see the field of view, and yes, the depth of focus can also be made visible. I would now like to get the camera mirrored on a plane, to simulate what is seen by the camera, when there is one or several mirrors in the field of view. Is this somehow possible? $\endgroup$
    – Wydolor
    Mar 10, 2016 at 11:01

1 Answer 1


I've made a tutorial for you to explain all the steps.

The essential part is that you can't simply mirror a camera along an axis you need to parent the camera to an object/empty first and then operate on the parent to mirror it. The video show other tricks like "clear parent inverse" to align a plane on the same camera plane. Also "Copy Attribute" addon was used to copy the rotation (but you can do it manually)

Hope this answer your question if it does upvote :)

  • 1
    $\begingroup$ Thanks a lot for your effort. However, I guess it's not exactly what I'm looking for. My goal is to have a "flexible" setup, where I can change the angle between the camera and the mirror with the idea, that the mirrored camera adapts accordingly. So far, I modeled the camera as a mesh and then I was able to use the mirror modifier. The drawback here is, that the modeling of all the camera parameters is quite complicated (variable depth of focus, sensor size, focal length), whereas a real blender camera object provides all those properties of the shelf and you could even render the result! $\endgroup$
    – Wydolor
    Mar 13, 2016 at 12:04
  • $\begingroup$ you can put a real camera inside the modeled one. And you can use trackTo constraint on the camera to always point to the mirror plane. Moreover you can use copy rotation constraint /with invert on the mirror axis on the second camera to mirror the rotation of the first one $\endgroup$ Mar 13, 2016 at 13:17
  • $\begingroup$ Good point - I'll do it like this. Thank you. $\endgroup$
    – Wydolor
    Mar 13, 2016 at 15:47
  • $\begingroup$ Unfortunately, "copy location / rotation" can not be used with a mirrored object, as long as the mirror modifier does not get applied. It would be nice, when a mirrored object could get accessed by name without being applied. $\endgroup$
    – Wydolor
    Mar 18, 2016 at 11:00
  • $\begingroup$ Basically it would be nice, when the mirroring effect could be modeled with "object constraints". $\endgroup$
    – Wydolor
    Mar 18, 2016 at 14:11

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