PDA

View Full Version : Editing hdr in Lightwave?


JDaniel
06-25-2003, 06:16 AM
If I load an hdr into LW's background or texture environment, tweak the exposure w/ image viewer fp, save the exposed as hdr, is it still a true hdr?

aurora
06-25-2003, 03:15 PM
To others please correct me if I'm wrong. Technically yes its still a HDR image because it is still saving all the extra intensity (greater then 255 RGBA) information as floating point and not as integer values.

JDaniel
06-25-2003, 08:19 PM
Hmm. What about rendering a sky you created in LW as an hdr? Is this a true hdr?

aurora
06-25-2003, 08:44 PM
I believe, and again somebody please step in if I'm wrong I'm not an expert on HDRI's, that the original image you create with SkyTracer is not an true HDRI. I'm assuming this because it is still limited to integer 255 values. Now however if you take that image into the virtual darkroom , image editor or a HDR specific app you can switch and crank the values to HDR based floating point values beyond the normal 255 integer limit. I'll play with it in just a little bit and report back.

minus
06-25-2003, 08:56 PM
Yes it's an HDRI as it keeps the exposure values over a certain range in the file information. --- To check just load your HDR in HDRShop and from there hit the + and - keys to see the different exposure settings in your image. -- You can lighten it in HDRShop just like you can in the LW Floating Point Image Viewer.... (Well very close to it anyway).

CourtJester
06-26-2003, 03:14 AM
Originally posted by aurora
I believe, and again somebody please step in if I'm wrong I'm not an expert on HDRI's, that the original image you create with SkyTracer is not an true HDRI.

That might explain some of the banding I'm seeing in some of the Skytracer HDR images on skydomes I inherited from the previous TD on my current project.

I DO know that you can build HDR skies with large values and multiple stacked layers of textures in Texture Environment, as I built one that worked perfectly with BG only radiosity. I was also able to convert it into a latitude-longitude (spherical projection) image using Eki's Refgen for use in my skydome light hack.

Edit: Hey Minus, I see you are in Minneapolis. There's going to be a LW meet at Wet Cement tomorrow night (Thursday, in Edina) will you be there?

CGTalk Moderation
01-15-2006, 01:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.