Speed up Mantra IPR

[-HEAVY-]

Is there a way to stop Mantra from regenerating Scene ?

at the moment I am working on some Shader and Texture work and and have only a Plane and a basic light and everytime I drop a node on to the IPR it regenerates the scene and makes my work for parameter changes very slow...
 

[davpe]

well i find refreshing mantra renders quite fast while working on shading. unless i do some displacement it doesn't even regenerate the scene on parameter changes in shader. principled shader thou seems to an issue as it has a displacement shading wired in a way it always regenerate even if you don't render any. so i just rewired it in a way it can be bypassed completely and saved it as a preset that I always use. not sure what is the problem on your side thou. also, i'm not sure what you mean by "everytime I drop a node on to the IPR".

if you want to stop mantra re-rendering the scene completely there is an Auto update button in Render view for that.

[-HEAVY-]

Hey David, thx for the reply and information,

and there it goes... I work on a bunch of displacement, to stack grains and noises on to each other... so it seems that this causes the scene regeneration.
maybe it helps when I disconnect all that displace output, work with the BW noise and plug the displace back into the Shader when done.

thx for the answer
cheerz to Prague nice city btw.

[davpe]

yeah generating displacement can take a while. in most cases thou, you don't really need to render a whole thing to see if displacement looks right. so just isolate an interesting part of geo and work with that until you're satisfied. also, sometimes it's a good idea to render displacement less detailed in early stages (by lowering Dicing multiplier) and then bump it up to finalize details.

cheers.

[-HEAVY-]

ok i check that dicing multiplier.

for now - and after seeing your first helpful answer - I control and setup my noises in a regular point VOP feed the output to Cd and have nearly instant feedback in the viewport. 
when I am satisfied I copy paste the noise to the shader context and combine with what I have so far.

[michaelb-01]

I'm having the same issue. Usually I render in Arnold and i'm used to very fast start and refresh times.

 

I'm developing my material at the top level (in /mat) then i'm going to collapse it into a material later. This way I can drag shading nodes directly onto geo in the ipr and it will make me a temporary material and render just that shading node - this doesn't seem to work if you are inside a material builder.. So i've isolate a small patch of my geometry, i'm rendering a very small region of the IPR and i'm rendering a unified noise just to tweak the parameters, but every time I make a change on the noise it re-generates the scene which takes a few seconds. It makes look dev very painful... Anyway to prevent mantra from re-generating the scene (only refresh the materials..?)

[michaelb-01]

Unified noise seems to be much worse than a turbulent noise. When rendering a unified noise the scene takes 3 or 4 seconds to generate, however with turbulent noise its milliseconds. Obviously unified noise is a much more complex noise but i'm surprised its that slow..