HDRI format

[Arkon11]

yes, could someone please explain this, I'd love to know aswell.

[Rens]

AFAIK:

- Light Probe: The original image, this one is used to create the other maps. Most HDR images are created by photographing a highly reflective sphere, like a mirror; this is the light probe.
Several pictures are taken, each one at a different exposure. These images can be combined into a HDR image with all the exposure information within.
I'm not sure what the use of this image could be if you already have the Spherical Map.

- Spherical Map: Like you said, you can use this as a map for a skylight (lighting) or as an environment/background map (reflections). This image has to be spherically mapped, i.e. onto a sphere.

- Crosses: These look like they can be used to make a VR image. Check out the following thread and open the .mov files: http://www.cgtalk.com/showthread.php?t=153809.

Hope this helps,

- Rens

[ahmedsheeraz]

HDRI is Hyper Dynamic Range Images which are mainly used to simulate realtime lightning in any 3d software.

These images have exposure ranges which are combined in hdr format in a software like HDR Shop.

Quick Tutorial (3ds max):

1. Apply hdr image in Environment map
2. Drag a copy in Material Editor and choose Instace. Choose Spherical mapping in drop down box.
3. Create a sphere and apply a material with raytrace map in reflections tab.
4. Render and u ll get a reflective sphere.

apply raytrace in refractions tab and u ll get a glass mat. Hope this help!

[Rens]

HDRI is Hyper Dynamic Range Images which are mainly used to simulate realtime lightning in any 3d software.
I think you meant to say that HDRI means High Dynamic Range Image and that they are mainly used to simulate realistic lighting. ;)

--

Also check out the following thread, I've explained some more there:
http://www.cgtalk.com/showthread.php?t=148308

Here's the complete tutorial on how to set up a HDRI file:
http://www.splutterfish.com/sf/contrib/tutorials/gabry_hdri_tut/_contents/index.html

-Short version-
1. Open file in the Material Editor (bitmap).
2. Make sure that Internal Storage is set to 16 bpc linear (the middle option).
3. Adjust the white clamp so that it's right on the edge where the pink clamp colours appear and disappear. Set it so they've just disappeared.
4. Copy the linear white point value.
5. In the material editor (ME); adjust the mapping under Coordinates to Environment and Spherical Environment. Also there, adjust the Blur value to 0,1 if you have any problems.
6. Also in ME, go to the Output rollout and paste the linear white point value in the RBG Level box. Adjust later if necessary.
7. Drag the map from the ME into the environment slot, choose instance.

For a skylight you might want to use a blurred version of the HDRI because sharp edges can sometimes give problems with the skylight. Still use the regular unblurred map for the environment though. So you could use one for the light casting (skylight) and one for the reflections (env. map).

Good luck,

- Rens

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