Hey, I got a little problem with HDRi Maps in Houdini. Firstly I cant load big files in the comp network, only direct into an environment light. The file ist 250 MB big. The node says I can incease the limit in the preferences but this doesn't work.
The more important problem: HDRI maps don't have the right brightness values when loaded into Houdini. They are basically to bright at the bright spots and to dark at the darker spots. Tried different color spaces, gamma, levels, converted it to a rat file…etc…when I bring the highlights down the blue sky gets almost black.
In Cinema 4D and lightroom I get it as it should be. Got an example picture attached. Upper one is Houdini.

Could be a couple things as to why the HDRI is not displaying the same. LUT or white point and black point settings. And the display not set to HDR.

Looks like you are viewing the entire image from 0 to max value and not thresholding by the white and black points.

All 16bit and above images should be treated as linear in Houdini then the display LUT is applied to correct.

Is this a viewport snapshot or a render in Mantra?

In the viewport display options make sure to enable “HDR Rendering” in the Effects tab. I save this as my default (press Save as Default button at the bottom right).

The default display setting for the Houdini viewport is set to 8bit. That will certainly clamp any display of HDR images in the viewport. Also makes preview of HDRI light setups in the viewport hard to work with.

thats actually a render. I converted the hdr to exr, rat but it just wont light light correct. also bought images from different sites like cg source…they never get imported into houdini like they should.

Here is another thread https://www.sidefx.com/forum/topic/48823/ [sidefx.com]

As i menteiond on the other thread, this seems like the case of gamma vs tonemapping. The results you're seeing in Lightroom may be misleading because it's always trying to beautify the images and not represent true pixel values (other than the display transform).
Have you tried opening the .hdr files in Photoshop and see if it matches with what you see in Houdini? I suspect that it does.

the only thing that did help was to repaint the sun in 32 bit mode into the HDR so it gets some actual intensity