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HDRI Rotation

Posted: Thu Feb 18, 2010 3:33 am
by jakchit
Something simple, but super cool and fun!

Try loading an HDR image and adjusting its rotations. This gives a super cool realtime lighting experience that was not possible before for me at least.

I love it

Re: HDRI Rotation

Posted: Thu Feb 18, 2010 6:28 pm
by gpu-renderer
I wish there was a scale feature :0)

Re: HDRI Rotation

Posted: Thu Feb 18, 2010 6:29 pm
by gpu-renderer
And also HDRI cloud cast mapping onto a model to simulate the sutle shades of enviroment and sunrays. (unreal engine 2 and 3 does this for games why not for octane) :0)

Re: HDRI Rotation

Posted: Thu Feb 18, 2010 7:29 pm
by radiance
gpu-renderer wrote:I wish there was a scale feature :0)
scale ?

how can you scale a HDRI environment ?
that's not possible as it's always got an infinite size...

Radiance

Re: HDRI Rotation

Posted: Thu Feb 18, 2010 7:32 pm
by Sam
A straight line is always the shorter path between two points...
Except if the points are not facing each other :lol:

Re: HDRI Rotation

Posted: Sat Feb 20, 2010 3:31 am
by PhilBo
I think they mean scene scale. Then you can control DOF and caustics better. That with HDRI rotation allows awesome control of the rendering experience.

Re: HDRI Rotation

Posted: Sat Feb 20, 2010 9:25 am
by Sam
Then you can control DOF and caustics better
True, in some scenes depending on the scale of the model its impossible to have the HDRI blurred
But the best thing would be that the dof slider goes beyond 10, sometimes 10 is not enough ;)

What does the HDRI scale change to caustics ?

Re: HDRI Rotation

Posted: Sat Feb 20, 2010 10:58 am
by radiance
well, you cannot scale HDRI's as they are infinite size domes around the render.
scaling the dome which does'nt exist would also make no difference.

scaling the scene might change things, and this will be possible in the near future with the transforms and instances on mesh nodes,
but then i would'nt recommend this at all as you'll lose your correct units and the whole texture system will be messed up.

Radiance

Re: HDRI Rotation

Posted: Sat Feb 20, 2010 5:43 pm
by gpu-renderer
If a hdri map is assigned what about using a 360 degrees single row panoramic image as a object in the scene would that still allow the hdri light to work on the main center scene or will block out light due to its size in the model.

I have 100mb 360 environment panos for displaying around some 3d houses. Trying to find the best solution + hdri in place. Hdri on its own looks odd due to scale issues and also the textures are always vertically stretched to high. Yet in a 2d paint program they have a perfect image ratio of 3:2.

HDRI maps do they use direct light or are they global illumination only.

i dont want this object to over shadow the main house model.

Any help would be welcomed

Re: HDRI Rotation

Posted: Sat Feb 20, 2010 5:59 pm
by radiance
Hi,

HDRI maps provide direct lighting / ambient occlusion light with the directlighting kernel, and both direct and indirect eg global illumination with the pathtracing kernel.
regarding scale,
we use latlong style images, so your aspect ratio should be 2:1 eg 2x as wide as it's height for example 2048x1024.
if you use a 3:2 aspect panorama you will get horizontal compression.

Radiance