View Full Version : mia_exposure Use_preview?

04 April 2007, 04:26 AM
has anybody gotten the preview option in mia_exposure to work. i've tried it on windows and mac and all i ever get is a red square? anybody?


04 April 2007, 03:26 AM
nobody likes mia_exposure?

04 April 2007, 06:23 AM
The use_preview and preview parameters are used to make the process of tweaking the tone mapper a little bit more "interactive". Do the following:

Disable the mia_exposure_simple shader.
Render the image to a file in some form of HDR capable format (like .exr, .hdr or similar), for example preview.exr.
Enable mia_exposure_simple shader again.
Set the preview parameter to the file saved above, e.g. preview.exr.
Enable the use_preview parameter.
Disable any photon mapping or final gathering.
Re-render. The renderering will be near instant, because no actual rendering occurs at all; the image is read from preview.exr and immediately tone mapped to screen.
Tweak parameters and re-render again, until satisfied.
Re-enable any photons or final gathering.
Turn off use_preview.
Voila - the tone mapper is now tuned.

taken from the archmat docs ;)

04 April 2007, 06:32 AM
thanks, but i'm one of those people that does like reading docs. is it working for you? i've tried it all sorts of ways and never got anything but a red square. anyway thanks for the reply.

04 April 2007, 01:12 PM
Yes, the method in the docs works perfectly (I used an .exr file). Just click on the checker box by the preview option, then link the rendered image into the MR file node that has opened. I hope this makes sense, I am not at maya to get the correct node names.


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04 April 2007, 01:12 PM
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