sIBL HDRI EXR free image and free soft...

[patro]

please consider that the ibl sets are made to avoid the use of big sized hdr during the rendering.... the bigger the image, the bigger the ram usage... if i'm not wrong a big sized hdr in Luxreder of about 150Mb can use uncompressed inside Luxrender easy 1Gb of your ram.
this tecnique is very useful in biased render since you can use different images for different purpose.
in Luxrender if you want to use a hdr or a exr as illumination and for reflection you just need the reflection hdr from the ibl sets but if you want that the used hdr is also visible as background, you need to look for big sized hdrs, because the use of an hdr/exr smaller then 8000X4000 will give you a fuzzy background.

[giuliojiang]

thanks for the answers

so I can just use the .hdr file. And the ones from hdrlabs aren't high resolution.
Now I'm using a very big .hdr from here http://www.openfootage.net/?p=349 it looks good but the dynamic range is not that good... I have to add a sun-only lamp to have good shadows.

[MaRo]

I have to add a sun-only lamp to have good shadows.

Speaking of which, it is often rather tedious to properly align the sun lamp in your scene to match the HDR.
(too bad one cannot preview the hemi in Blender to manually adjust the sun position in realtime)

You probably have noticed the little .ibl file that comes with some of the sIBL from HDRLabs...in some of them, there are flat coordinates for the sun (relative to the flat HDR). it is in a [Sun] section, and they are called SUNu and SUNv.

Anyone fancy doing a little math to transform that into proper position for the sun lamp?

Another solution could be to use the Geographical Sun plugin in Blender, as in the [Header] section of the .ibl file, you may find GEOlat, GEOlong, Date and Time. Once set up, you just have to play around with the TimeZone of the Geographical Sun plugin?

[patro]

MaRo, yes this is what is needed to can work with hdrs and a sun light in a scene.
we max user have a plugin from hdrlabs that can import all the data from a ibl sets, create the sche lighting and match the sun light with the sun of the hdr.
the script is full automated. I did a request for you blender user on a a blender forum in the script section... but no one were interested.

what you can do in blender is to create a sphere, latlong map it with the hdr, create a sun lamp and match te sun with the sun position in the hdr, link one to an other. rotate the sun or the sphere now so to can match your desidered lighting. hide the sphere on render and give to the hdr used as background in luxrender the same rotations as the sphere. this is how you could work with in the mean time.

for the use of the ibl sets, Aldo Zang did a plugin for luxrender in the past... it is working very well but at time it's not included in Luxrender. it would be nice to has it. it create a new infinite light in which you can load 2 or 3 textures, the base texture is the high resolution jpg, the other are the small hdrs for illumination and reflection. the plugin give a great ram win. the plugin avoid that the small hdrs are painted above the big jpg background by avoiding to fuzzy it.
hope that Jeanphi will include it into Luxrender.

[MaRo]

Thanks for the heads up, Patro.

Nice tip this latlong mapped sphere. If we link the Z rotation of it together with the one of the sun and the hemi tied to the hdr, then yes, it should work fine. I'll give it a try.

I'll also have a look at this plugin by Aldo Zang. It reminds me of something, but I sure overlooked it in the past.

[patro]

Maro, since you are so interested in the plugin... give a look to this thead
viewtopic.php?f=10&t=5381&hilit=ibl
the point of Jeanphi is right because we need just to use a big sized hdr for the lighting, the problem is that there are only few free big sized hdrs to download.
the plugin would give us the liberty to use the hdrlabs database... and why not, to create our own sets

[Abel]

Regarding support for the IBL file format, you might find this thread interesting as well: viewtopic.php?f=16&t=6875

[MaRo]

Thanks Abel!

Good to read that it is in the "todo list" now
It's the kind of feature that look almost insignificant, but they are indeed very helpful, and could save quite some time when setting up the lighting.