Photographing environment reflection spheres

[Tom Bussey]

Can someone help me get something straight in my head? When phographing for reflection backplates or sphere maps to use in the Vray reflection override slot for instance, where should the photos be ideally taken from?

 

My instinct says near where the camera target would be, but happy to be proved wrong.

 

Also when put in the environment slot, do spherical maps essentially centre themselves around the origin, or is there more to it than this?

[Tommy L]

Here's some reading for ya:

http://www.hdrlabs.com/tutorials/index.html

[Tom Bussey]

Thanks, I've not found my answer in there yet, but that seems like incredibly useful info all the same. I'm currently trying to raise the funds to get hold of a proper camera set-up to give this a go so that info will be invaluable.

[eduardasvuskvariokas]

Didn't done this myself, but from what I've read on various sites, to create spherical images (hdris too) you can use either probe ball, or use camera with a stand (whatever that thing is called in English). When shooting with probe ball you want to be as far away as possible and be zoomed in as much as possible. The only reason for that is that you aren't visible in reflections. So there is no magic number or length how much you need to move, so just experiment with it and fit to your liking. When shooting with camera and stand you literally take like 12 photos (every 30 degrees) on three different vertical angles (30, 60, 90) and use some program to make it a spherical image. Then make hdri if needed (will need 36 photos for each exposure). Since on this one you won't be visible, there shouldn't be question where to stand

 

As for the center of picture, it will be probe ball if you use it and if you use camera 360 method then camera will be the main object around which the surrounding is mapped.

[Tom Bussey]

I missed this reply, so thanks for that, but I think you misunderstood my question. It was relating to the real-world photography, not so much what's done with it in the 3D programme after. I understand the process of taking/stitching a HDRI / equirectangular backplate.

 

Imagine you are on site, with buildings around a site where a client wants to build a glass tower. You are 50 yards away from said site taking the photo which you will put your rendered 3D model into, that's easy. Now, you want to capture the equirectangular image to use for reflections, or HDRI for lighting, as you describe. In order to get the surrounding buildings in their correct positions in the reflections, would you capture this image from the position of your first photo, or the base of the unbuild 'subject' building, if so to the left or right of the site?

 

I'm thinking maybe there is no correct answer as the reflection can never be correct for more than one particular point on the building. i.e. the point at which you captured the equirectangular from. if you capture it from where the front door will go, the left and the right of the building will show reflections a bit offset from what they really would be.... Whether that's enough to notice is doubtful but is important to me in this case.

[Stephen Thomas]

You would want to capture it from the centre of the site of the proposed building.