Setting 3D Camera to have the same position as the Null object.

[Yiannis72]

Hello!

I would like to ask the following question...
I have an interior area of a 3D building and I want to place the Camera inside the building. I want to find a way to parent the 3D Camera to a Null object in such a way that the position of the 3D Camera is exactly the same with that of the Null object. When you parent the 3D Camera to the Null object the traditional way, then the position of the Null object is exactly the position of the 3D Camera's point of interest. But I want to rotate the camera itself (and not its point of interest) around the Null object.
It is very easy to do that. You simply copy the position of the Null object to the position of the 3D Camera and then you parent it to the Null object. Then you can orbit the 3D Camera around the Null object. 
The problem, though, is that you cannot see the Null object in order to animate it since its position is exactly the same to the 3D Camera's. You can see it only if its position would be the one of the point of interest of the Camera. 
How can we take care of this issue? I know there is an expression but I can't remember it.

Best regards!
Yiannis.

[Justin Taylor-Hyper Brew · Accepted solution]

Sounds like you're trying to do a few things, but if your issue is not being able to see the null object your camera is parented to in order to animate, switch to 4 Views and animate it from another camera.

[Yiannis72]

Very good idea...  Thank you!

[Rick Gerard · Accepted solution]

All you have to do to match the position and orientation of a Null to the camera is hold down the shift key and parent the Nul to the camera.

Then reverse the parent so the null moves the camera. 

Anytime you are in a meeting or arranging 3-D layers it is always a good idea to have at least two views open.

[Yiannis72]

I think though, there is an expression that you can parent the camera to a Null, the traditional way (where the Null has the position of the point of interest of the camera) but (using this expression) the camera behaves like the actual camera (and not the point of interest) has the exact position of the Null. I think Cramer had a tutorial about this... I cannot remember... I don't think it is difficult. I will try to make an expression like this, so that you are able to see the Null object even using only one view...