<div dir="ltr"><div class="markdown-here-wrapper" style="font-family:"Lucida Sans",Cantarell,Verdana,sans-serif;color:rgb(11,83,148)"><p style="margin:0px 0px 1.2em!important">Just so I understand correctly, you have two volumes in the same viewport and are interacting with each separately. Is that the case? Or do you have two different viewports? Do you see the same issue on a different graphics card?</p>
<p style="margin:0px 0px 1.2em!important">As far as performance, I agree if you’re not changing any other property on the volume, viewport size and image sample distance should be the only factors affecting rendering.</p>
<div title="MDH:SnVzdCBzbyBJIHVuZGVyc3RhbmQgY29ycmVjdGx5LCB5b3UgaGF2ZSB0d28gdm9sdW1lcyBpbiB0
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Y3RvcnMgYWZmZWN0aW5nIHJlbmRlcmluZy48L2Rpdj4=" style="height:0;width:0;max-height:0;max-width:0;overflow:hidden;font-size:0em;padding:0;margin:0">​</div></div></div><br><div class="gmail_quote"><div dir="ltr">On Wed, Mar 21, 2018 at 10:36 AM ianl <<a href="mailto:ilindsay@insigniamedical.co.uk">ilindsay@insigniamedical.co.uk</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Just to be clear, I am interacting with each volume in turn for a few seconds<br>
each. It appears that one of the volumes gets cached onto the card and is<br>
performant, but not the other, no matter how much I interact with it.<br>
<br>
I have done some more experimentation, and down sampling the volumes makes a<br>
significant improvement to performance. This seems to imply some swapping<br>
on/off is going on. Incidentally, GPU-Z shows plenty of GPU RAM left<br>
(~700MB), but I don't know how accurate this is and of course it does not<br>
give me any idea how fragmented it is.<br>
<br>
Am I correct in assuming that once the volume data texture is loaded into<br>
GPU memory, then performance should only depend on<br>
ImageSampleDistance/viewport size i.e. the number of rays cast and<br>
SampleDistance i.e. the sample spacing - (in mm?) along the ray? Having less<br>
data at a wider spacing to sample through should not make a difference to<br>
performance, only quality - or is this a gross simplification.<br>
<br>
Thanks,<br>
Ian<br>
<br>
<br>
<br>
--<br>
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</blockquote></div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div class="inbox-inbox-inbox-inbox-inbox-inbox-inbox-markdown-here-wrapper" style="font-family:"proza libre",sans-serif;color:rgb(0,56,107)"><h5 id="inbox-inbox-inbox-inbox-inbox-inbox-inbox-sankhesh-jhaveri" style="margin:1.3em 0px 1em;padding:0px;font-size:1.1em;border-bottom-width:1px;border-bottom-style:solid;border-bottom-color:rgb(238,238,238);font-weight:bold;color:rgb(11,65,148)">Sankhesh Jhaveri</h5>
<h6 id="inbox-inbox-inbox-inbox-inbox-inbox-inbox--sr-research-development-engineer-kitware-http-www-kitware-com-518-881-4417" style="margin:1.3em 0px 1em;padding:0px;font-size:1em;color:rgb(11,83,148);font-family:"open sans",sans-serif;font-weight:normal"><em>Sr. Research & Development Engineer</em> | <a href="http://www.kitware.com/">Kitware</a> | (518) 881-4417</h6>
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