OTOY Forums

Hi, is it possible to have true floating point output from Octane? The highlights seem to be crushed although I choose, openEXR as output?

The EXR untonemapped used with the EXR half precision option disables should write complete unclamped image files. The EXR tonemapped can have the highlights crushed if you are using, for example, a camera response or other tone mapping features.

Thanks,
-Juanjo

Hi Juan

Thanks for the quick reply.

Is this also the case when saving an image from mplay? if I use the exposure preview controls in mplay, the whites are still crushed? Are there other settings in the rendertarget node?

The gamma and exposure controls in MPlay should not affect the floating nature of the image. The limitation is in the Octane tone mapping functions related to the camera response. The camera response is done using LUT curves that are only defined for the display range, so all other floating information above or under this range is clipped.

Thanks,
-Juanjo

Hi Juan,

Thanks, would something like vignette of the camera response also limit the dynamic range?

I am not sure, but I think that if you set the camera response to linear, you should get a unclamped HDR image.

-Juanjo

Hi Juan

Thanks the images are unclamped now, however, I have issues with the alpha channel - is this stil 8bit? When I for instance really push the image in after affects it looks fine, however, the "alpha edges" become hard/harsh. Is this a limitation with alpha? This is my first project where alpha channel is required. I guess i could probably use a separate alpha or maybe it's simply an after effects issue/setting with the exposure filter.

The reason for this workflow, is that I can't predict the lighting intensity all the way through the animation, therefore being able to "capture raw" and then simply adjust the exposure in ae works well - especially if I can get the alpha working properly.

The alpha channel should be also a floating value, but it a value in the 0..1 range. I suppose that you can't push the alpha channel and the RGB values at the same time. You should extract the alpha channel before process the RGB data.

Thanks,
-Juanjo