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how to hdri?

Posted: Sun Apr 24, 2016 4:44 pm
by Sorel
is there a way to make my characters/objects look like they're in an hdri instead of...tiny and out of place? I'm using an 8k image here

Re: how to hdri?

Posted: Mon Apr 25, 2016 9:11 am
by erik-nl
This is something I actually know a thing or two about ; )
For this to work you need to somehow 'recreate' the room in which the spherical image was made.
- Your render camera must be in the position where the real camera was in the room: in the centre of the image-sphere, and at the same height above the floor as the real camera was.
So your render camera needs to be at the origin of 3D space, at point 0,0,0
- The floor where you will place your figures and/ or props will have to be lowered accordingly.
If you didn't create the spherical image yourself you will have to guesstimate, but usually about 1.5 meters is about right.
- To help you position your figures and/or props correctly in 3D space in relation to the spherical image, it can be useful to actually place primitive planes of appropriate dimensions in the scene where the floor and walls would have been.
You normally wouldn't render them, but these planes can sometimes also be handy for catching (or casting) shadows.

In short, if at the time of creating the spherical HDR image it would not have been possible for a person to stand between the camera and the wall of the room, then you cannot possibly place a figure in that position in your render without it looking odd (to say the least).
Looking at a 'flat' 360x180 degree image, everything seems too small and far away from the camera.
To get a much better impression of the room (or landscape) you will have to use an interactive viewer for equirectangular images, like DevalVR Player.

Hope this helps, cheers!

Erik

Re: how to hdri?

Posted: Mon Apr 25, 2016 7:20 pm
by Spectralis
This discussion interests me because I have quite a few HDRI's but find it difficult to choose which ones will work in a scene. Some HDRI's are created without any particular place and seem to be lighting only (possibly for portrait lighting) while others are of lighting from a particular place (for indoor or outdoor scenes.)

I've tried to augment the lighting by using emissive surfaces to get a more naturalistic effect when using figures in a scene. I'm not sure if that's correct but it seems to help. Is there a book or website that explains in depth how to use HDRI's and which ones to buy?

Re: how to hdri?

Posted: Mon Apr 25, 2016 8:28 pm
by erik-nl

Re: how to hdri?

Posted: Mon Apr 25, 2016 10:01 pm
by Sorel
Thank you Erik. I did try what you asked but my stuff still does not look like it "fits" in the scene. I will have to try more experimentation I suppose.