iray iterations? 1 iteration?
Mistara
Posts: 38,675
iray iterations? 1 iteration?
i'm rendering an iray straight to image.
is there a way to make it all done in 1 interation?
how do you tell iray to keep rendering til zero noise?
thanks!
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Iterations are sample passes. One iteration would mean one sample per pixel, which is not nearly enough. So the answer is no.
There are hundreds of threads on this subject, with a lot of good information already detailed.
but, rendering straight to image, i don't see the passes.
it can't do it all in 1 pass?
Nope...
That's the way this type of renderer works. You do get a slight 'boost' by not having to update the viewport/render window, but it is a very small one.
while rendering to file is better for biased renderers, in this case with a PBR renderer you are better rendering to a window, you can then stop it when the noise has disappeared, the same applies to Luxrender, Octane etc.
No, it takes several passes to get enough samples for most pixels to converge under almost any lighting set up.
doh
As mjc notes, the overhead for updating the messages and even the picture window in the callback loop is pretty small (The output window is not the "canvas" that you see mentioned in the render history window; that canvas is something internal). However, if things are taking longer than you'd like, there are some optimization settings you can TRY, though they are arcane, and may not have a significant enough benefit to bother with.
Open the Progressive Rendering pane, then the Update sub-pane (this isolates the settings to just the ones you want), and look at the Min Update Samples and Update Interval settings. The default settings should be adequate for most cases, but play with one or the other to see if you can affect render time and quality. To have Iray update the canvas less frequently, set Update Interval to a higher number. I don't know of any Daz-created documentation on these settings, but the Iray programmer's manual provides some useful, if somewhat cryptic, info:
http://www.migenius.com/doc/realityserver/latest/resources/general/iray/manual/index.html#/concept/progressive_rendering_photoreal.html
Note that you must be using Photoreal mode to see and set these values.
the3Ddigit is correct that if you're doing single images, it's better to be able to see the picture as it renders, so you can terminal early if you feel it's warranted. The straight to file option is handy if you're doing an animation out of the individual frames that are saved.
Iray doesn't work that way. It doesn't do an "all at once" render like 3Delight, it processes the scene over and over, getting closer every time to what us users would consider a good render. Instead of 3Delight's "run once", Iray keeps going until it hits one of three stop conditions; either time (default 7200 seconds or two hours), number of iterations (default 5000), or convergence ratio (default 95%). This last is the closest Iray has to a measure of "completeness" as we'd understand it, and there is a gotcha; since convergence always approaches but never quite reaches 100%, you must never set this to 100% (although you can use a value just a tiny fraction less than that, but be prepared for a long render). These parameters are on the Render Settings tab, Progressive Rendering subtab.
Note that the default values, especially for convergence, are not "high quality" settings — you will need to tweak things to get improvements. Also, sometimes the thing that needs to be adjusted to reduce noise to an acceptable level will be your scene's lights or materials.
thanks.
two hours is no way long enough.
i don't understand what convergence means?
writing to image file, i see a lot of writing to canvas messages,
starting to realize my personality not compatile with the zen of iray,
i end up reciting the serenity prayer. lol "things i cannot change things i cannot change"
i need a beginning and an end, with no noise artifacts.
At the risk of over simplifying... the percentage convergence is the percentage of your image that has stopped changing.
Simplification or not, this is an excellent definition.
(There are some exceptions, like Iray's penchant of considering "noisy neighbor" pixels in the convergence estimate, but by in large, "stopped changing" is exactly what's going on.)
makes sense !