Creating HDRI skies in Bryce using CGIskies.com-type images

BrycescaperBrycescaper Posts: 148
edited March 2015 in Bryce Discussion

An important element in Bryce's realism are the atmospheric effects- and seeing how DAZ never scaled up the atmospheric effects from the old Corel scale, the realism if interacting haze color and density to create realistic atmospheres- just like in real nature- has sadly fallen by the wayside. Those who have Bryce 6+ have no idea what infinite control one could have over creating the atmospheric ambiance of a scenein Bryce versions up to Bryce 5.5, the last Corel build of Bryce to which Daz added the DAZ|Studio import option, was the best and most realistic in keeping with the scale Corel developed. The color and density of haze controlled the sky and cloud cover, It was designed just as in nature.

The subject has been rehashed over the last eight years, and keeps popping up everytime someone imports a large scene or object from DAZ}Studio and finds a heavy thick haze that in DAZ's exaggerated scale appears to be fog rather than haze. One suggestion made by Hiro or David Brinnen years ago was to turn off gamma- but that turns off the atmosphere completely, and what you have is DAZ}Studio with nasty watercolor skies with odd sky dome colors.
It looks like something Sydney Pollack painted while he was drunk :shut: .

Thankfully, Bryce introduced IBL (image-based lighting) through HDRI, so the color of haze and fog can be changed without impacting the color of the sky itself. You can still create the atmospheric ambiance you want, (because the haze and fog controls are still there) but not at the expense of the entire sky's realism. Ingenious too because HDRI introduces universal global lighting, which is more realistic than strategic balls of light supplementing the lighting effects you want.

Enough of the history and tutorial, I have a specific question about creating HDRI skies using your own images.

I have in the past used 360 degree panoramic skies (not HDRI's but actual 360 panorama images) from places such as cgiskies.com. I just re-installed Bryce on my new Win8.1 system ( I was a hardcore 7 user, but it was locking up and such), and I can't remember for the life of me how to do it again. I have quite a few images I've done with my HDRI images, and I now have an expanded collection of skies I'd like to incorporate in new scenes. I've cheated and pulled up previous scenes and re-saved the skies as newHDRI category in my sky presets. I'm interested in creating new skies, how do do this? I thought 'use image' works, (I thought I did it that way before, perhaps I'm mistaken but it only uses imported HDRI images).

Post edited by Brycescaper on

Comments

  • HoroHoro Posts: 10,636
    edited December 1969

    @brycescaper - in general, a jpg re-saved as radiance (hdr) doesn't make it to an HDRI. A spherical panorama (360° x 180°) can make a beautiful backdrop. There is no need to convert the JPG to HDR, just create a huge sphere and map the image spherical on it and put the camera in it. If you use a JPG as HDRI (after converting 24 to 96 bit) gives you also a nice backdrop and it will also cast some ambient light onto the scene, but no key-light, even though the sun is in the sky of the image. The dynamic range is still only 256:1. However, this can be compensated by putting the Bryce sun over the sun in the image.

    If you want to create new HDRI capable skies from Bryce skies, you're a bit limited. You do get a true HDRI but the sun is not very strong. It can be boosted but there's a limit. The clouds created in Bryce are always in the best resolution, whether you render as 800 x 600 or 4000 x 3000 pixel document. If you create an HDRI from a sky, you have to boost up the size and this eats up a lot of memory and fills the sky library in no time - and if you render large, you still notice that the resolution is not sufficient.

    So creating lovely skies and saving them to the sky library seems the better way to me. When you use this sky for a scene, make the sun invisible, create an HDRI at 600 pixel diameter, make the sun again visible and do not use the HDRI as backdrop, just use HDRI Effect to generate believable ambient light, adjusting the colour with Saturation.

    I have some PDFs on my website (see sig) that may interest you. Go to Bryce Documents > Mine > Sky. "Exporting an HDRI retaining full Dynamic" may be the most interesting for you. If you have specific questions, please don't hesitate to ask them. The whole theme is huge and I could go on for pages and just drown you. Specific questions are safer.

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