HDR (or other automatic lighting in fact) file requirements...

n.drju_6d88cb4c15

Good evening everyone!

It's been ages since I logged last time. Maybe DAZ Studio is simply so easy to use?

Maybe... But automatic lighting with HDR use leaves me stumped... If you could be so kind and answer these questions for me?

1. What are the file requirements (size, pixel aspect, bits/channel etc.) for an environment map file to work? I tried several of them, to no avail... And I also can't seem to even open the properties of a default hdr file! (the low definition one with ruins or something).

2. Why an .exr image that I rendered in Planetside's Terragen is not working in DAZ Studio 4.8 if the dialogue box explicitly states that .exr images are supported for enviro maps?

3. Is there any free program that allows easy and reliable conversion from .exr (which I can produce) into .hdr (which I cannot) file type?

4. If everything fails, is it possible to provide automatic lighting with other file types? .png, .bmp, .tiff are preferable.

5. If above is possible, again, what are the file requirements for these files to work as enviro maps?

I ask fifth question in particular because while supplying a circular camera image in .png format, the lighting was not present at all... The image was simply bright, with no shadows, no directional light, and a small shading speck directly underneath my model.

Any and all help will be appreciated. I don't need pixel-perfect solutions mind you - the easier the answer the better. Specifically, the easiest way out for me would simply be to use other types of files instead of hdrs, until I can update my graphical programs.

I am also uploading my very, very crude spherical camera jpeg that I planned to use as a test enviro map. Unfortunatelly, I am unable to load the .exr... You can check it out and, if possible, tell me what the heck is wrong here.

n.drju_6d88cb4c15

No answers... hmmm. That's uncalled for...

Nevermind anyway, I found everything out myself.

DrunkMonkeyProductions

probably no answers because nobody really has a bloody clue how to answer them

 

I'm a bit twisted and will see if i can give some satisfactory answer.

1. What are the file requirements (size, pixel aspect, bits/channel etc.) for an environment map file to work?

none really.

The only real requirement is that they have a radiance channel, various terms for this,  in addition to standard rgb.

this will take say an 8 bit image to 16, or a 16 to 24 etc.

what this does is provide an additional 0-255 per channel, RGB, this defines how "bright" a particular pixel is for determining how much light it produces

The format is actually irrelevant whether it's EXR, HDRI, or Tiff as long as it contains the additional data, heck even jpg formats can have it.

 

"I tried several of them, to no avail... And I also can't seem to even open the properties of a default hdr file! (the low definition one with ruins or something)"

If you're just downloading images with HDR or EXR it may be that they are not for lighting use, meaning they  lack the 4th channel i mentioned.

The lack of seeing "properties", i'll assume windows os, may be due to the version of windows you're running, as most versions don't support HDR out of the box.

I can't speak too specifically on this however as i only use Server versions and currently 2012r2, which doesn't suffer this issue.

There are hdr viewers on the net, including one from microsoft for Win10, which may provide that information.

 

2. Why an .exr image that I rendered in Planetside's Terragen is not working in DAZ Studio 4.8 if the dialogue box explicitly states that .exr images are supported for enviro maps?

while i don't work with terragen much anymore it could simply be that the particular exr created does not contain the raidance/luminance data.

Check the save options when creating the exr for this option, if available.

It's also possible that even using the EXR format it's using a proprietary algorithim or adding data that iray can't use.

 

3. Is there any free program that allows easy and reliable conversion from .exr (which I can produce) into .hdr (which I cannot) file type?

just change the file extension, instant HDR.(JK)

Daz studio can use either format, and more, for IBL(image based lighting) via the Environment chanel under Render settings tab.

It's not the format that matters, it's that fourth channel that matters, if that fourth channel isn't there it won't work.

 

4. If everything fails, is it possible to provide automatic lighting with other file types? .png, .bmp, .tiff are preferable

technically yes.

Just about any format can have a raidance/luminance channel.

It just depends on the particular software it was created in or converted with.

the primary reason to avoid those other formats is that they may not produce the results you want as the compression may be of the 'lossy' type which can result in grainier images and funky lighting results.

 

5. If above is possible, again, what are the file requirements for these files to work as enviro maps?

the only requirement is that it contains the fourth channel.

Size, file type, pixel density, etc are all completely irrelevant.

 

HDR, EXR, JPEG, TIFF, etc are just compression formats, the contained files can be exactly the same with the exact same data, to an extent.

Think about the difference between a ZIP and a 7zip.

same contained files, just a different algorithim to achieve the result.