Messages

1

[Max] Feature Requests / Re: The most wanted feature?

« on: 2016-10-18, 10:27:49 »

A temporary work-around, sure. But quite far from the sharp lines you get from, for example, vray toon. In any case: Being able to get this from Corona with a one-click solution would be extremely useful for me anyway.
And if you find the time to implement it, please make it possible to get it as a render element. In vray, you have to go through the trouble of making a separate render if you want a clean line render.

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[Max] Feature Requests / Re: Displacement Lister

« on: 2016-10-17, 15:10:31 »

Agreed! Very good idea.

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[Max] Feature Requests / Re: The most wanted feature?

« on: 2016-10-17, 15:07:18 »

Thanks for making it even clearer, Juraj. I thought "hidden line" was a fairly well established concept in the 3d community. Another example would be the default viewport mode of Sketchup.

But yes, a basic toon shader (without the ability to do any cel shading) is what I am after. Very useful when the architect requests a "sketch" kind of visualization.

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[Max] Feature Requests / Re: The most wanted feature?

« on: 2016-10-17, 14:48:20 »

http://imgur.com/a/LPmV6

Like so! That image is comped on top of a white GI render, but preferrably, the output of a render element would be black lines on an all white base.

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[Max] Feature Requests / Re: The most wanted feature?

« on: 2016-10-17, 13:48:09 »

I think you may be... it's not that I want it to display hidden edges in the mesh, but rather an "outline only" display. Typical Vray toon outlines render, or the "Hidden Line" viewport shading mode in 3dsmax.
Afaik, wire tex displays the full wireframe of the model.

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[Max] Feature Requests / Re: The most wanted feature?

« on: 2016-10-17, 12:02:50 »

One thing I'd very much like to see, is a hidden line shader - preferably as a render pass.
I'm rather new to Corona, but haven't been able to find a method that works satisfactory. Coming from Vray, and I have often the use of their Vray toon to create hidden line renders. However, having it as a map/render element makes more sense. A possible solution would also be to add a "hide interior edges"-button in the WireTex map?

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[Max] General Discussion / Re: Doble-sided material

« on: 2014-10-26, 17:14:22 »

Well well... what do you know! I gave it some further thought, and managed to solve the problem.

I took the front and back map, multiplied them with a composite map, adjusted the brightness with an output map. Adjusted the brightness of the front and back diffuse maps (to counter the dimming that occurs when using translucency).
The best Fraction value seems to be 0.45. Going higher makes the front side darker than the back side, which never(?) occurs in reality.

Conclusion: You can really make this work in Corona. Gonna make an attempt to create some nice leaves...

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[Max] General Discussion / Re: Doble-sided material

« on: 2014-10-21, 12:02:09 »

Actually, that's wrong. The material should get dimmed, because it passes some energy through instead of reflecting it back to camera.

Well, there is the problem. What goes on, in real life is that the surface absorbs all light, it then scatters within the object, before exiting the object. The light that exits the object either goes 100% back to the surface (no translucency) or 50% back (full translucency). The value in both vray and corona for full translucency (within thin objects) can never occur in reality, because the backside of the object becomes brighter than the lit front side.

As I said before, my view is that of a 3D artist, and not a programmer, so I'm sorry I can't explain it better. What I did in the discussion with Chaos Group was to set up a real life study, and then try to recreate it in rendering. So far, all attempts have been unsuccessful. ;)
I've set up a similar scene for Corona, which I'm including to this post. The setup there is just to illustrate the different translucency values 0, 0.5, and 1, and how they look when lit from the front, and the back.
I'll also include a photo I took of how things look in reality. From a rendering point of view, I think it's interesting to note that a thick stack of paper will look exaclty the same as a single sheet of paper, when lit from the front, even though the stack lets hardly any light through.

I hope someone manages to beat me here - I'm not here to prove Corona wrong, just for the sake of it - I'm just here to shed som light on the problem, and try to find a solution.

The .rar-file contains a max2015 file with the scene, and the textures used. The weird black line in the render is simply the corona light seen from behind. ;)

9

[Max] General Discussion / Re: Doble-sided material

« on: 2014-10-20, 18:25:12 »

Hehe nice to hear it. I think Vlado understood the problem eventually, but so far, no fix has been applied.

From a workflow point of view, the 2sided material works nicely. If you look at a leaf, the front and the back side will have completely different properties - the diffuse color and reflection/glossiness will be the most apparent ones. Just setting up each side as a separate material, then dropping them in a 2sided mat to add the translucency is a great idea. With front/back map, you will have to do a lot more tweaking within the material. Also, being able to simply switch between different front and back materials is easy when using the 2sided mat.

The main issue with the example in the thread over at Chaos, is that the backlit side isn't shown correctly on the other side. Also, when setting the material to the "correct" level of translucency, the material is significantly dimmed when lit from the front. Alas, this works exactly the same way in Corona. When setting a map in the Translucency slot, the material front side is dimmed, the higher you set the Fraction amount. This is not what goes on in reality. A thick piece of paper and a thin paper will look exactly the same when looked at on the lit side, but the backside of those two papers will differ a lot.

I tried to find articles explaining the way light is dispersed and reflected through leaves. (I made a thread about that on Chaos aswell haha!) I found this article, which I think is rather interesting, though I haven't set out to understand the maths of it. http://www.photobiology.info/Jacq_Ustin.html

I would imagine a perfect double sided material to work in the following way:
• Each side maintains the diffuse/bump value independently from each other
• Each side maintains the reflection/specular value independently from each other
• A translucency value directs how much of the incoming light that transmits through the object - a fill color should also be added, to simulate e.g. chlorophyll

Also, to look real:
• A fully translucent material should look the same as a non translucent one when lit from the front
• A fully translucent material should never look dimmed or darker than its back side

These points are open to debate and improvements. :)

Now, I totally see the issue with energy conservation here, and since I'm no mathematician/programmer, I can't say how to solve it. As an artist however, I can say when something doesn't look right, and so far, the double sided solutions for vray and corona are not right. ;)

(I wonder if what rendering software lacks is correct absorption and transmittance of light within objects?) 

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[Max] General Discussion / Re: Doble-sided material

« on: 2014-10-20, 15:16:36 »

This question has been on my mind since I first decided to try out Corona, that since it's been on my mind ever since Chaos Group introduced the 2-sided material for Vray. Why you ask? Well, becuase Vray's 2sided material isn't accurate! It does not render the way a real life flat, translucent material would do (i.e. a sheet of paper or a leaf).
I wrote a rather lengthy post about it at the Chaos Group forum: http://forums.chaosgroup.com/showthread.php?69901-The-2-sided-material-real-life-study-vs-the-rendered-version . If you don't have access to the site, I could probably repost it here, if you want.

I REALLY hope Corona can implement this, because it would enable us to render foliage (and more) in a much more realistic way.

By the way, I was not able to get a correct result using the Corona front/back-map. But who knows, maybe I'm missing something? :)