DMC sampler in modo?

[Lenscowboy]

Hi Guys,

I've been reading about the DMC sampler in tutorials and online but I can't find it in vray for modo. As far as I can see there are only 4 options in the vray globals:
1. Fixed
2. Adaptive
3. Adative Subdivision
4. Progressive

Where is the DMC? Am I missing something?

[vladimir.nedev]

These options are hidden on purpose, with the idea being that you won't have to modify them in most cases.
You can find them in the "Channels" panel with the "Render" item selected, they are near the very bottom.

Greetings,
Vladimir Nedev

[jonmoore]

Interesting that you consider these settings should be hidden. I've always tweaked these settings over the years to get rapid feedback. Good to know where they reside though.

Tweaking these settings during the look-dev phase of a project is especially important as I'm looking to assess broad lighting/surface settings overall (but don't mind noise). Typically my settings will be (I'm providing them for other beta testers that might not be so so familiar with V-ray and for Vladimir as an example of my workflow):

For each of these I globally use 8 or less samples in each of the shading/lighting subdiv settings

Low Preview Quality: Adaptive amount - 1, Minimum Samples - 8, Adaptive Noise Threshold - 0.02, Global Subdiv Multi - 1
Medium Preview Quality: Adaptive amount - 0.8, Minimum Samples - 128, Adaptive Noise Threshold - 0.005, Global Subdiv Multi - 2
High Preview Quality: Adaptive amount - 0.733, Minimum Samples - 128, Adaptive Noise Threshold - 0.004, Global Subdiv Multi - 4

These compare to the fixed Modo settings of:

Adaptive amount - 0.85, Minimum Samples - 16, Adaptive Noise Threshold - 0.005, Global Subdiv Multi - 1

On a simple HDRI lit scene the low quality preview provides a 'broad brush stroke' preview in under ten seconds on my test system (at 720p), medium preview quality x7 longer, high quality preview x10. All of these base settings provide very fast previews and the high quality preview settings are accurate too (but obviously still a tad noisy). Once I'm happy with my scene I can de-couple the 'Global Subdiv Multiplier' (set it back to one 1) and optimise my scene's sampling for lights, materials etc on an individual case basis (making judicious use of region renders to keep the workflow snappy). My final DMC settings are identical to the fixed Modo settings although I'll often need to use an Adaptive Noise Threshold of 0.003 for tricky indoor renders.

I do understand why you've made the decision to 'hide' these global DMC settings in the channels panel as very small changes have a dramatic impact on performance if you don't know what you're tweaking; but having the ability to quickly lower these settings during the look-dev stage of a project (when it's all about rapid feedback) is essential.

Maybe you could provide a preset system for the DMC if you'd prefer to keep the DMC stuff hidden in the channels panel (similar to a simplified SolidRocks plugin that's available for Max and C4d).

IMHO the current method of hiding these settings in the channels panel will cause more problems in the long run because most users new to V-Ray in Modo will most likely gain a lot of their knowledge from the multitude of 3rd party 3ds Max/Maya tutorials scattered about the net and it will be frustrating when key settings appear to be hidden from them (and I would guess that many typical Modo users steer clear of the Channels panel).

[vladimir.nedev]

I can put the "DMC Sampler" options under the "Image sampler" roll-out, in a roll-out that is collapsed by default.

Hiding them was Vlado's idea and I think it is based on the changes in image sampling and the new "Min shading rate" parameter in V-Ray 3.0.
If he is ok with it, it will be pretty easy to show the DMC sampler options. I don't understand the artist's workflow good enough to make this decision myself.

Edit : MODO's UI is static, since it is written in .cfg files that ship with the installation and can't be scripted, so a global option that just hides/unhides the DMC sampler options will be hard to implement.
What I can do, is add an option "Use default DMC sampler values", when checked, the default values will be used and all DMC sampler options will be hidden and ignored.
So this option will be a quick way to revert to the defaults.

As for presets, these should probably be part of a "Quick settings" dialog similar to the 3ds Max one. But that may come at a later stage.

Btw, you can save the whole Render item as a preset (right click on it, Save Preset...), in case you need to quickly switch between different sets of settings (image sampler/ gi-no gi / etc...).

Greetings,
Vladimir Nedev

[jonmoore]

That sounds like a great idea (if Vlado agrees).

I think the typical Modo V-Ray customer will be more akin to a typical C4D customer (VrayForC4d). Lot's of independent studio's/designers, without access to the DR processing fire-power of typical Max/Maya customers; so artist friendly workflows that work for mid range set-ups too will be ideal. It's more cost effective for these guy's to pass on all the heavy lifting to farm rendering solutions but this isn't workable during the look dev / art direction phase of a project.