[yt-users] volume rendering brightness

[Britton Smith]

Hi Geoffrey,

The brightness of the total image is basically normalized to the brightest
pixel.  Occasionally, when you rotate the domain, a single pixel will be
incredibly bright which will cause the rest of the image to be dim by
comparison.  You can fix this in with the snapshot call by adding the
keyword,  clip_ratio=some_float.  This limits the maximum brightness to no
more than a fixed number of standard deviations from the mean.  I recommend
you start with a clip ratio of 5 or 6 and play around with it.

Briton

On Mon, Feb 27, 2012 at 7:57 PM, Geoffrey So <gsiisg at gmail.com> wrote:

> Hi volume rendering experts,
>
> I was playing around with a density volume render of a tiny cube on my
> laptop, everything went smoothly, however, I notice a change in "overall"
> brightness between images when I did a rotation.  I'm not sure how to
> explain this, but it seems that from images of different angles, sometimes
> the average brightness is consistent, but sometimes it suddenly drops and
> the image would look about half as bright, and after a couple frames it
> would light back up.
>
> I'm guessing this is after each image is ray casted, it gets normalized to
> a certain value, and that value changes depending on the angle?  Is there a
> way to pin the brightness between images so if I make a movie it won't dim
> and light up as I rotate?
>
> Also I was wondering if I'm the only person to notice this? (the only
> other post I found about volume render brightness is about AMR cell
> contributions)
>
> From
> G.S.
>
> _______________________________________________
> yt-users mailing list
> yt-users at lists.spacepope.org
> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.spacepope.org/pipermail/yt-users-spacepope.org/attachments/20120228/a02e92cc/attachment.html>