Volume Material - Inside Mode

[jojorender]

Hi all,
can someone please shine a bright light on the “inside mode” feature in volume materials. Yes, pun intended.
It’s not clear to me how this feature is supposed to work and can’t find any info about it.
In my test, I can’t see a difference between ‘on surface” and “inside mode”.

[TomG]

It needs a 3d input to one or more of the channels (absorption, scattering, emission). For example, the native Cinema 4D Noise shaders, set to Object (or World) mode. You could use a texture map, but it would have to be projected through the volume in some planar mode.

You can see the examples from Max which are the same thing, at https://forum.corona-renderer.com/index.php?topic=21091.0

It's ideal for fog or mist that has structure to it, or even more solid objects. Sneak peek from the Corona Renderer 4 for Cinema 4D release blog that shows the difference (this was a C4D noise into the Absorption channel only):

EDIT - PS if time allows I will re-render this with a smaller Step Size to smooth it out some :)

[jojorender]

Thanks Tom, that helped.

The helpdesk for max features some sample scenes with volume mats used (max only).
Once Corona 4 is out, maybe we c4d kids can get some sample scenes too?
That would really help to get started with volumes.

Maybe this was asked before, but will the c4d version get the Corona Volume Grid?
For example a realistic fireplace fire seems to be a real challenge in arcviz and from the samples on the max helpdesk,
being able to load .vdb's will do the trick.

[TomG]

The Max scenes are incredibly simple, as are the C4D ones like the test shown above - since they contain no textures or objects of any complexity (so, no third party items, just stuff you can create in seconds in C4D) they are easy to share, don't need any special permissions, and are quite tiny. So, sometime after release we'll make those simple ones available, such as they are :) The will be just a sphere, or sphere and cube, with one volume material applied etc, but you can at least take a look at how they were set up and get to grips with how it all works.

For OpenVDB support, best thing would be to post it in the feature requests section, there's nothing on the roadmap plan for it at the moment.

[dirktorrijos]

I made this super quick after downloading the new nersion of Corona today. It's two primatives, a light and a plane. Take a look at it and you'll see how simple it is to get something with volumetric shading pretty quickly. Just used a couple of noise shaders and played around until they felt OK. I used an HDRI in my sky, but used just a light material in the attached scene.

https://imgur.com/Jtine1Y

[atoneontail]

Love this and takin notes now!

Would love for more tutorials... on Inside Volume. Currently testing out your material and enabled the emitter as well. Getting some cool "planetary" type effect. Will post render when it's done. Only on the 8th pass @ 12 min on a 4.2 iMac mid 2017 5k 32ram

Loving this new update btw!

[atoneontail]

Heres the same material dirktorrijos created. Just added emission to the material, than added a red corona light to demonstrate how lights outside of the object (sphere) effects the inside volume of the sphere, in combination with emissions from the inside volume. Not the prettiest render, just for discussion.

I really wanna would like to know how the spinning light ball effect was achieved in the Corona 4 release video.

[TomG]

Hi! We should have all three scenes from the video uploaded at some point soon - they are all very simple. The rotating light "lighthouse" was just a cube, volume material applied to it with noise in the absorption if I remember, then a disc Corona light with some directionality inside the cube and spinning. The "electric sphere moving around" was a cube with volume material, with noise multiplied by the native Proximal shader into the Emission. The Proximal shader pointed at a sphere object, then the sphere is simply animated moving through the cube volume, which makes "those parts of the volume inside or near the sphere glow".

We should have those for you soon I hope, plus a "bonus exterior fog on a landscape" scene not in the video. All are just test scenes of course, for you to deconstruct to see how the inside mode works.

[TomG]

And they are live!

You can download them from https://corona-renderer.com/resources/models, down at the bottom of the page :)

[edofante]

It needs a 3d input to one or more of the channels (absorption, scattering, emission). For example, the native Cinema 4D Noise shaders, set to Object (or World) mode. You could use a texture map, but it would have to be projected through the volume in some planar mode.

You can see the examples from Max which are the same thing, at https://forum.corona-renderer.com/index.php?topic=21091.0

It's ideal for fog or mist that has structure to it, or even more solid objects. Sneak peek from the Corona Renderer 4 for Cinema 4D release blog that shows the difference (this was a C4D noise into the Absorption channel only):

EDIT - PS if time allows I will re-render this with a smaller Step Size to smooth it out some :)

ok! but no option to use ground distance, like on 3ds max? I don't find any special shaders on cinema4d

[TomG]

Not sure what you mean by "ground distance" - the native Proximal shader in C4D should be able to do that, see the example with the glowing electric sphere, which uses the Proximal driven by the sphere (you would just create a Proximal driven by the ground, same as Corona Distance would be used in Max). Just because there isn't an example in the downloads doesn't mean it isn't possible :) Combining the approaches from the sample scenes will give a huge range of possibilties! I just happened to like the clouds as clouds rather than ground-hugging mist for this example scene :)