Questions about V-Ray 3.6

I am learning V-Ray now and I have some questions …

Well, I just created something (model) and clicked Render, I did not use Lights. Where is the light from, how does it work?

Where is it at all?

light by default is coming from a studio hdri image linked in your environment settings

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Found :sweat_smile:

And where is the camera located by default? Can I somehow manipulate her easily? Or here only by 2 points (V-Ray Camera component)?
P. S. In a pinch, you can use Get From Rhino Viewport, but it’s inconvenient to edit the camera …

Help me please!

Why does rendering happen in squares, and sometimes just noise is calculated for the final?

These settings generally affect the rendering that I run in GH?


Why not first get yourself familiar with Vray outside grasshopper?

There are two modes: progressive and non progressive. The latter renders in buckets (that’s what the squares are called)

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Switching between bucket and progressive rendering is at user’s hands, so it is not “sometimes”, but rather whatever you decide. There are pros and cons for each mode. I’d suggest you take a look at V-Ray documentation first. It explains the theory as well:
There are also webinars and courseware videos lectures available.

by the way the noise is not “calculated”, it is removed. That is the nature of photorealistic rendering - the renderer is shooting rays from the camera towards the scene to decrease the uncertainty in the color of each pixel.
Much like in the quantum mechanics, but without destroying the poor particle

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Well, it turns out, and I study V-Ray in all directions :slightly_smiling_face:

Oh, that’s what’s the matter … Thank you so much! :smiley:

@Nikolay, thanks for editing :sweat_smile:
Here are some subtleties and a link :yum:

The default camera is taken from the currently active viewport in the Rhino window

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It is precisely said

I read the help, but still I can not understand this thing … In the beginning everything is simple, but further: GI, Reflection, Refraction, SM - I just do not understand. :slightly_frowning_face: Who has already met with these parameters, can you explain their logic / interconnection / meaning to me? If it’s not difficult for you, please attach a simple example of using in practice :pleading_face:


During ray tracing if a ray hits an imaginary sphere encompassing the scene (called Environment) its color is modified with the color of the specific pixel at this location of that environmental sphere.
These controls allow you to specify different environmental spheres depending on the type of the ray that hits them - e.g. a reflection rays will hit the reflection environment. Shadow, camera, etc. rays will hit the background sphere.
For example you can have a reflective object, that is surrounded by a solid black background color, but reflects as if it is surrounded by a clear blue sky. Like this:

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Background: any image in there means it gets used for:

If you want however a different GI light than your background, you can override it, by using the lower slots.
Example: say you want not to see the background (clear white) but do want to see it in your glass reflections and reflections. Then you place the (HDRI) in the GI, Reflection and Refraction slots and remove the image from background and make the color simple white.
Secondary matte: don’t know this, never used it

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@Nikolay, @Gijs, now everything is clear :slightly_smiling_face: Thanks for the detailed answers!

A few more questions … I just do not understand :pensive:

  1. Does it seem to me, or does Denoiser speed up rendering? Somebody knows?
  2. If I adjust the Denoiser settings and click Update, then I adjust it again and click Update, 2 will the operation go over 1 or what?
  3. How exactly does Effects Update Frequency work and why is it needed at all?

From SketchUp Help:

Update Frequency – Controls the regularity of denoiser and lens effects updates during progressive rendering. Roughly this specifies the percentage of the total render time that is allotted to the effects evaluation. Larger values cause the effect to be updated more frequently. A value of 100 causes updates as often as possible. A value of 0 disabled the updates during progressive rendering. Effects are applied after the rendering process is finished and are not applied if the rendering process is canceled.

From Rhino Help:

Effects Update Frequency – Controls the regularity of updates during the progressive rendering. Roughly this specifies the percentage of the total render time that is allotted to denoising. Zero disables updates during the progressive rendering; larger values cause the denoiser to be updated more frequently; 100 will cause updates as often as possible. Values ranging from 5 to 10 are usually sufficient.

:confused: :thinking:

No. It’s a post render operation to reduce noise.

Point2 update just means using the then current render result as a basis for the denoise process

Point3. No it is not needed and I would recommend to just manually update or only at the end of the rendering.

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Well, but 1 operation (and others also) keeps somehow separate (changes are possible), or the result of rendering has already passed correction (is it irreversible), then the following operations (Updates) are put on top of the current render?

Okay, then just 0 for Denoiser?
Help: Values ranging from 5 to 10 are usually sufficient :confused:

Yes just 0 for denoiser (no updates) because otherwise you will waste time for denoising intermediate results.

Again, the current render result is used as basis for the denoise and effects. Current render result is what you see if you show the rgb channel (the denoised will be in its own layer as well as in the effectResult layer)

On the other side you can save time and render to a rawer noise level. So, if an undenoised rendering looks good at noise threshold 0.01 you could try to render with 0.02 and denoise it. So, you could get your rendering done in a fraction of the undenoised version.

If you need a very clean image you would need quite long render time, for example for interiors. But killing the last fine noise per denoiser instead per longer render times can save a lot of render time.

So, the answer of your question could be yes and no.

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