Can i save different lighting levels into a single image somehow?

[pailhead]

I thought that .exr 32bit format would do this. A part of my image - the outside that can be seen through an opening in my window is seriously overblown. If i change the exposure in the VFB i can set it so that i actually see some detail in the otherwise white patch. But once i save this as an .exr, and when i try to set the exposure in photoshop, the whole patch simply becomes gray.

What am i doing wrong?

[vlado]

Which 3ds Max/V-Ray version is this?

Best regards,
Vlado

[Clifton Santiago]

Sounds like its not being saved as 32-bit. With 32-bit EXR you should have full float exposure. RC3?

[pailhead]

Vray 1.5 (it's not the sp1), max 9 64bit.

[crazy homeless guy]

are you asking if you can control the intensity of exterior and interior lighting independently within one image?

[pailhead]

Not at all, i am asking if its possible to control the exposure of the image after it's been moved from the VFB into something else, via some format like .exr.

Basically, the result of moving the exposure slider in VFB is something completely different than moving the exposure slider on an 32bit .exr file in photoshop.

[vlado]

Ahh, photoshop. Does it actually keep the data as floating-point internally?

Best regards,
Vlado

[sv]

Not at all, i am asking if its possible to control the exposure of the image after it's been moved from the VFB into something else, via some format like .exr.

yes absolutely, you can do this.

Photoshop (at least CS2 & CS3) do keep it as 32 bit, and you can certainly change the exposure and reveal details that are otherwise blown out & over exposed.

It sounds like the exr isn't being saved properly as 32bit - are you using the VrayFB save function, rather than the 3dsMax one? It sound's like your saving an 8-bit .exr, which the 3dsMax save function might do, but not the vray one.

[pailhead]

I'm saving it as a 32 bit .exr, i'm on the edge of a nervous breakdown. It seems to be working with some, and not with others, but i'm using the same settings every time.

I'm also having weird antialiasing issues in those overblown areas.

[ene.xis]

to fix the aa issues on the overblown areas try to use the sub-pixel maping option in ur colormaping setings

[Clifton Santiago]

You may be telling it to save as a 32-bit, but it may not be actually saving as 32-bit. Save out of the VFB just to be sure, or save as vrimg and convert to EXR.

[sv]

yeah, as clifton suggests, the .vrimg format will definitely save as 32 bit, so try extracting the exr from this. Just to show you this was a recent render where i had the camera settings way wrong but in 32 bit you can, as your asking, reduce the exposure as you can in the VFB.

[pailhead]

I kept rendering and saving as .exr with this on mind, but i was unpleasantly surprised when i found out that a lot of those would simply gray when i lower the exposure.

So, the bottom line is, if you save it as .exr, you should be able to both lower and raise the exposure and you will get correct light levels. It's not one way, i.e. it can go brighter than the current but not darker, and it is supposed to work?

It may be a bug or something.


If i save to vrimg, and then export that to .exr, it shouldnt fail? Or even if it does for some reason, vrimg should have all this data in it?

[Clifton Santiago]

To test to make sure your image is floating point in photoshop, increase the exposure until its completely blown out... say +5 exporsure. Save. Close. Re-open and decrease -5 exposure. It should look the same as before. If not, then its not full-float.

[ene.xis]

also make sure u set the exr options correct when saving the image from vfb:
format:float - 32 bits per channel