Can you make good HDRI with Carrara?
Oso3D
Posts: 15,004
I've played around with trying to make HDRI with Carrara and Picturenaut, but I can't seem to make anything with decent lighting (the image looks fine, but the lighting makes me think the HDR is not properly spread out)
Tips? Doom?
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My own inept experiments with this have led me to believe that the answer is no, not really or maybe, depending on what kind of HDRI you are trying to make. You can certainly use Carrara as part of the process to make an HDRI, but whether or not it is good or not depends mostly on your standard for "good." :)
Mark Bremmer has a tutorial on using Carrara and Photoshop to create an HDRI. It works pretty well for faux studio light environments but for more complex scene lighting I think you are better off finding a free one somewhere. Here's a link to his tutorials: http://www.markbremmer.com/3Bpages/darkarts.html
Experts in the process, please feel free to correct me. My entire experience in the matter consists of one weekend of playing with it. :)
I have made a couple with the standard Carrara renderer, it requires (as you may know) to render several images at different "exposures", however Carrara does not have a built-in exposure system, so you need to fake it by adjusting the intensity of all lights. You also need a way to make your lights visible so they show in the renders. Even then it can be very hit and miss.
You may be interested to know that Octane definitely and maybe Luxrender/LuxCore can save a rendered image as an HDR directly, but in EXR format. You can then convert that to a .hdr file in Photoshop.
Deleted because of double entry,
You can try rendering with different gamma settings (for instance 1, 2, 3). It should give you enough range for decent lighting.
When importing in picturenaut, specify two EV difference for each (0 for gamma 1, 2 for gamma 2, 4 for gamma 3).
I will try to post an example.
You also have to remember that invisible lights (distant, sun, bulb, spot) are not transferred in HRDI. If you need strong lighting, it better to user visible light sources (shape light, anything glow, glow channel...)
I picked up some of Dimension Theory's 'Skies of...' sets in the sale yesterday, and from the experimenting I've done, the HDRI isn't capable of lighting a complex scene on its own. (maybe if you just have one small prop, say a car or something and nothing else, it'd be adequate). If you turn up the intensity enough to light the scene, the sky becomes bleached out. So you need to add extra lighting.
HDRI seems to disable the "Sun" light, so I had to convert mine to a Distant one. (Dimension Theory's sets come with a distant light preconfigured, but of course I "thought I knew better" :roll: ). DT's "sun" is set at 60%, which is basically peeing in the ocean. Bung on an extra zero and tweak from there. 500% seems to give a decent result. I've got a render cooking & I'll post it when it's done.
It can depend on how many levels the HDRI was created from. With enough levels to truly capture the brightness of the main light source, a good HDRI can adequately light a scene, although you will always get a degree of softness of the shadows. For sharper shadows, more contrast or just that bit more control of the lighting, then adding one (or two) extra lights can be very useful.
In Carrara, you can adjust the intensity of the background (in the Scene tab of the Assemble Room) separately from the lighting effect that it gives (Sky Light in the Render Room), so you can increase the lighting effect without bleaching out the background.
If I understand correctly the first post, the issue is with using Carrara to create a HDRI.
When doing that, it's a good idea to keep the most significant light sources to make the new scene and use the HDR file to simulate global illumination.
I have an other idea I have to test, but maybe it would be possible to use "baker" plugin to bake the specular map on a sphere instead of using spherical camera. This way, you could have a map of the light received at this point. Mix it with a baking of a reflection map for the colour, composite them outside Carrara and you have either a good source for HDRI or for LDR (map) lighting.
I'll investigate that because it will allow the incorporation of lighting in the source. it may be quite interesting.
Nah, bad idea. Baker light map doesn't include specular. Too bad
The Luxrender plugin Luxus can save in the OpenEXR format and it is on 48% sale now:
http://www.daz3d.com/luxus-for-carrara
Free OpenEXR viewer: http://www.hdrlabs.com/picturenaut/
Rendered one of the presets in Carrara and saved in in 32bit and 8bit in Luxrender: