hdri maps and skymaps...

im using an hdri map for an architectural viz - and i really really like the light quality - but i dont like the blurry hdri image in the background…is there a way i can use an hdri map (light probe) and a skymap together in blender?

…im rendering with yafray.

hmmm…no bites…bummer.

okay, here’s a quick example of what im asking about, this model is lit with an hdri probe, but the background is blurry n stuff. is there a way i can add a skydome without sacrificing the hdri light setup?

http://img280.imageshack.us/img280/699/hdritest40hg.jpg

Not sure what this technique is called, but what if you used another object to block out the background. Here I just threw in a plane, extruded a couple of times, subsurfed to make it a nice smooth transition on the horizon line, angled up and sized to fill the camera view. (simple application of matlib 102 materials)

This is lit completely with an HDRI skymap. (Yafray render)

http://img56.imageshack.us/img56/3104/hdritest5zc.jpg

sounds good, but it blocks out some of the probes emitting rays…

its a great plan b, but i was hoping to render with the hdri map invisible or with a different background or dome…

Hmm, hadn’t thought of that. wonder what other options there are?

Hi originalsurfmex:

There’s posts in the forum at www.yafray.org. about transparency for compositing. You can either edit your yafray xml file generated by the render as described in the yafray forum or render with alpha channel. (rgba) in blender. You’ll then only get your hdr visible to an extent in your reflective surfaces like windows, so try to choose a hdr that has the environment to match the setting you intend putting your model in if you’re going to then comp it.

EDIT.

http://www.yafray.org/forum/viewtopic.php?t=456&highlight=&sid=a77b954d6ed9b9c71f746d2cc4655e74

How to use the keywords:

http://www.yafray.org/forum/viewtopic.php?t=343&highlight=alphapremultiply&sid=a77b954d6ed9b9c71f746d2cc4655e74

awesome! thanks a million.

Yellow,

Good link, but in just setting the RGBA channel on render I’m seeing the background. (Tried PNG output format so I’d assume to have the alpha channel available)

The render block section of my XML file only shows the save alpha setting going on.

Do you know if we have to manually place those ‘alpha_premultiply’ and ‘alpha_backgroundmask’ parameters in the XML file? And then how do you push that XML file into yafray without using blender?

The Yafray site is woefully short on simple user instructions. eg. is it as simple as >yafray /tmp/YBtest.xml ?? or are there required command line switches?

>>>
render camera_name=“MAINCAM”
raydepth=“10” gamma=“1.000000” exposure=“0.000000”
AA_passes=“2” AA_minsamples=“4”
AA_pixelwidth=“1.5” AA_threshold=“0.05” bias=“0.001000” clamp_rgb=“on”
background_name=“world_background”

save_alpha="on" >
<outfile value="/tmp/YBtest.tga" />

<<<

Compared to setting to RGB only

>>>
<render camera_name=“MAINCAM”
raydepth=“10” gamma=“1.000000” exposure=“0.000000”
AA_passes=“2” AA_minsamples=“4”
AA_pixelwidth=“1.5” AA_threshold=“0.05” bias=“0.001000” clamp_rgb=“on”
background_name=“world_background”
>
<outfile value="/tmp/YBtest.tga" />
<<<

Doh! weird issue I’m having. I was basing my ability to still see the background upon the image that gets thrown up at the end of the render from within blender.

If I closed that, and the pull the actual TGA file (or PNG, or TIF) into Gimp then the background is gone.

So I guess setting the RGBA button alone did work.

DracoFodder:

“If I closed that, and the pull the actual TGA file (or PNG, or TIF) into Gimp then the background is gone.”

Ha, you beat me to it. Confused me the first time as well.

Good to see you and originalsurfmex are still around. :slight_smile:

:confused: still around …ok, cool thanks i guess :slight_smile:

btw, super nice work on your blog yellow…between that and Elbow3D’s thread i hope we get some good stuff archivizually. I

i’m hoping to move away from design renders and into final presentation renders in upcoming months.

Is there a way to disable an object from effecting/being effected by radiosity in YafRay? If there is you could just put a plane behind the object(s) with the desired background mapped and scaled to fit the view port.

the first thing i did was add a dome on shadeless with all shadow options off (traceable, shadowbuf, shadow, trashadow etc)…and i also turned it on “bounds” in the viewport.

unfortunately it blocked out the effects of the light probe.