Wire physical camera focus

[RichardBlank]

Is it impossible to wire the physical camera focus distance?

[Svetlozar Draganov]

It is possible.
Just turn on Specify Focus checkbox and wire Focus Distance parameter like any other parameter.

[RichardBlank]

I have done that but it does not seem to update in the viewport?

[Svetlozar Draganov]

Which V-Ray/3DSMax version you are using.
The viewport updates properly with V-Ray 3.10.01 and 3DSMax 2015:


Scene: http://ftp.chaosgroup.com/support/sc...usdistance.max

Would it be possible to test the attached scene and let us know how it behaves in your environment?

[RichardBlank]

Ok the problem seems to be wiring a tape to the focus.
http://we.tl/w1VE8OLNO3

[Svetlozar Draganov]

The Lenght parameter is locked - that's why the Camera Focus Distance is not updated properly.
If you activate Specify Length check-box it should work as expected.

[RichardBlank]

Yes it works, but its pointless to use the Tape in that case. What I want is to lock the focus plane to a position in space.

[Svetlozar Draganov]

This is how the Tape Length works unfortunately, it is not a limitation of V-Ray Physical Cam.
Wouldn't be possible to use V-Ray Physical Cam Target in order to determine Focus Distance?

[RichardBlank]

I've done it many times in maya but I haven't found a way to do it in Max. The problem with using the camera taget is that most of the time I'm animating cameras I don't use a targeted camera. Maybe its possible to wire the taget distance from another camera?
Anyway I requested it as a new feature http://forums.chaosgroup.com/showthr...era-auto-focus

[Svetlozar Draganov]

Then you can use ExposeTransformHelper.
This tool could also measure the distance between two objects and then you can wire its Distance Parameter to VrayPhysicalCam Focus Distance one.


Here are two sample setups:

http://ftp.chaosgroup.com/support/sc...distance01.max - this one use two dummy objects parented to the box and the camera.
ExposureTransformHelper calculates the distance between them and then pass this value to VrayPhysicalCam.

http://ftp.chaosgroup.com/support/sc...distance02.max - this is basically the same idea but instead using additional objects the distance is measured directly between the box and the cam.

The following script could be also used to bake the focus distance between a specific objects and VrayCam.
http://www.scriptspot.com/3ds-max/sc...mfocusdistance
The downside of it is that you have to bake the focus distance again if the animation of the focus object or cam is changed.

[RichardBlank]

It works perfect! Thank you so much