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Topics - marchik

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Gallery / Dichroic Glass shader + Tutorial
« on: 2022-07-26, 18:12:21 »

A series of renderings made from a reference to illustrate my tutorial on creating dichroic glass shader using the Corona Renderer.

Architect: Pete Kennon
Photographer: Timothy Kaye

Project on Behance
Post on my Telegram channel
3ddd gallery

The tutorial itself:
English version
Russian version

I would like to take this opportunity to once again ask our favorite developers for a separate thinfilm shader, and a layered shading system so that we don’t have to invent such non-standard approaches, Ondra, please! :D

Once again I want to raise this topic, but with a more thorough request.
Recently, I needed to do product images with a focus on photorealism, and once again ran into the annoying limitations of my lovely Corona in this matter.
We have a nice customizable DOF effect inside the corona camera, with almost all the necessary settings, and even the ability to add a custom image for the aperture shape, but...

Chromatic Aberrations
The first obstacle was the actual impossibility to add proper chromatic aberrations when using DOF inside corona, in case of any post processing methods to add this effect we have to blur or distort the images even more, summing this blur with the already existing DOF effect on the render

Adding a geometric lens with dispersion in front of the camera or simulating aberrations using a custom aperture shape image cannot correctly reproduce different types of aberrations that depend on the geometric position in the frame field and the lens scheme itself. Of course, in my question I turn to the wonderful DOF Pro plugin by Richard Rosenman, in the corresponding section on his website it is described in detail about different types of chromatic and achromatic aberrations and what exactly influences their appearance.
some examples

At the moment I don't know of any way to add longitudinal and lateral achromatic aberration to an image with an already existing DOF effect other than manually

I created a fairly complex setup in Fusion that adds different types of aberrations and mixes them using a Z-Depth map, but firstly, this approach seems to me not very user-friendly, and secondly, where you can manually refine on static frames, this will be impossible to do when rendering animation

Lens Flares
At the moment, we can only add Lens Flare effect when post-processing in third-party packages, although even real-time engines such as Unreal Engine and Yebis system inside Opengl rendering in Substance Painter/Designer can do this, and our ultra-realistic ray-tracing proudly CPU-based engine simply can not, I think this is a slightly strange omission, with all due respect.

Lens Dirt overlays etc
I will not talk about additional effects that can be added in post-processing, but which are much more efficient to simulate inside the render engine itself, because. for their correct imitation, each user needs to know at least the basic structure of optical schemes, use additional plug-ins, and so on, while the render engine, working in an interconnected system and receiving complete information about the image, can reproduce such effects much more accurately and correctly.

Current Situation
Speaking of the current situation and Corona's commitment to simplicity and user-friendliness, at the moment the user can control the shape of the aperture in 2 places independently - in the Custom Aperture section of Bloom & Glare, in and Bokeh section in the camera settings, meanwhile, these 2 parameters absolutely independent and if we set the bladed aperture in the camera settings, glares will still be calculated for circular and vice versa.
I think this confuses new users, and does not add convenience to the old ones, because in order to correctly simulate a photorealistic image, you need to manually link all these parameters, and I have already said about those effects that we cannot imitate with all our desire.

What do I suggest
Given all of the above, I came up with the idea of ​​one universal LensConstructor, which in its interface would cumulatively collect all the parameters that are responsible for all lens effects and would allow using a limited number of parameters and presets in the form of pre-made optical lens schemes to set the appearance of all these effects.
Schematically, I suggested how it could look, and it can be located in  the camera settings, similar to the current opening tonmapping window, otherwise it can be finalized from the current custom aperture shape interface that is in the bloom and glare settings.

The aperture shape created using the constructor or a selected preset from the most popular 10-15 photo and cinema lenses should control all effects at the same time, including both bokeh shape and glare, simplifying user interaction with our engine and providing additional features.

PS In the current iteration of the development of the 9th version, you have prioritized the refinement of existing features and I perfectly understand that these features are not a priority, and in general these effects remain the lot of enthusiasts, but I want to remind you that caustics used to be like that, and now any user can access it using one checkbox, thanks to you and thanks for your attention!

Gallery / Gaea's Bosom
« on: 2021-08-31, 02:55:40 »
Gaea's Bosom artwork.

Non-commercial project done in spare time. 
PhoenixFD for the waterfall and ofcourse our beloved Corona Renderer :D

Hope you like it!

[Max] Bug Reporting / Small typo in corona sky model hint
« on: 2021-07-22, 01:42:40 »
It seems to be the first report for the 7 release :D

Gallery / Kōdō
« on: 2021-02-01, 20:30:28 »
Kōdō artwork

Small non-commercial project done in spare time :D  by the way, using new Corona physical shader,
smoke simulated in phoenixfd.

Hope you like it!

[Max] Feature Requests / Background material
« on: 2020-05-30, 23:36:22 »
Today I came across an interior scene in which I needed to use a Jpeg background stretched onto a plane and at the same time a visual display of corona sun outside the window with bloom and glare, and using the standard background approach described in corona's helpdesk with rayswitch cannot help me. If I had a full panorama, I would use direct visibility override in the scene settings but I don’t have it and translating this jpeg into a spherical projection and trying to catch it in the window is too time-consuming.
So I got an idea - what if we have a standalone shader for the background with all the necessary overrides, settings, and maybe additional features directly in it, it would be very useful for newcomers as well.
In about 3/4 of all interior scenes, I add the background directly to 3ds max and not on postprod, and in half of these cases I use regular jpeg. Maybe I just don’t have enough knowledge or experience and I don’t understand something, but how, for example, can I solve this problem with displaying the sun through the background?
I think that if you think over and develop the idea, it will be very Corona-style, we will get a quick and easy-to-use tool for the tasks that visualizers constantly face in their daily work, especially considering that corona is mainly used in exterior and interior visualization

[Max] Feature Requests / Corona VFB portrait orientation
« on: 2020-03-05, 17:29:14 »

Guys, can we get an option to shrink the VFB window to this “vertical” layout with buttons on the left instead of at the top, it can be usefull for people with 1 monitor setups

I would like to ask the developers how the work on implementing foam and splashes support from phoenixfd is progressing, can we expect it in v6?
Is there hypothetically a technical possibility to implement motion blur support for a changing topology or to create a separate CoronaMesher that works with motion blur?
Soon I will have to render some fountains and I would not want to use other engines, since I stuck to Corona.

Guys, I need your help!
I have a complex scene that i created in 3ds max 2018 and corona 5, then I upgraded to 2020.2 and now I need to return to this scene and continue working.

The problem is - when I open this scene in 2020, 3ds max just crashes. I can merge all the stuff into a new scene, but after saving and opening 3ds max continues to crash. Empirically, I found that it was Corona render, because when you remove Corona render completely - the problem disappears.
Alternately isolating the layers and "save selected" to new separate scenes, I found out that the problem concerns objects, the materials of which contain a distance map.

And now i need to find  all my objects with distance map. Unfortunately I dont know the MAXscript and therefore I need your help, plz)

More and more often I notice that it is more convenient for me to use Corona scatter instead of Forest pack, it does not have such a messy interface and in most cases it does its job perfectly.
There is only one case left where I have to use Forest - scattering along the spline.

Let's say we have a curbstone and a complex spline with different Z-coordinates of the vertices (spline and box.jpg)

Let's create corona scatter and Forest and we can notice that the orientation of the boxes is slightly different. In the case of Forest, the boxes are oriented strictly upwards and in the case of Corona scatter, they are rotated along "local spline axis".
(scatters_Top_view_comparison.jpg and scatters_perespective_view_comparison.jpg)

We don’t have many controls to adjust the orientation of objects. In the case of Corona scatter it is "align to normal" and in the case of Forest pack it is "follow path X and Z" (Scatter along splines controls.jpg)

And as we can notice - changing these parameters does virtually the same thing, but this does not solve the problem because we lose the orientation of objects along other axes.
(Corona scatter align to normal 1.jpg and Forest follow path Z unchecked.jpg)

Can we just have an additional "make it straght!" checkbox that aligns objects like in a forest pack?

PS many thanks to the devs for the wonderful render engine and attention to user requests!

I have noticed this issue after installing Corona 4 Release version, when i create simple metal (or mirror-like) material with ior 23-999 and glossiness between 0.7-0.99, rendering models with material applied becomes weird and slow, its happens both for IR and Production rendering in all complex scenes no matter of lighting, with hdri or simple Coronalights, caustics on and off, with new lightsolver on/off, the only thing that helped me is a fresh scene with one sphere in it) then it is rendered well.

I attach screenshots of comparison between the 5th and 25th pass
I want to upload GIF but it is too big)

3ds max 2018
Windows 10
Xeon E5-2683 v3

Hello, I have noticed, when I setup my material using for example 3 maps like diffuse, refgloss and normalbump and when I want to use triplanar projection i have to setup triplanar map, then copy it 3 times and spend some time connecting pins.
And every time I want to change and tweak triplanar projection i need to do it again, copying 3 times and connecting pins, considering that we cant see triplanar changes in the viewport and have to use IR, all that stuff becomes really annoying.
What if we could use multiple inputs  in CoronaTriplanar map  and multiple outputs for every texture we want to use with triplanar(choosing desired amount) or maybe CoronaTriplanarModifier with selectable desired UV channel. It will be great! I am not doing "photoshop-hypothetical" screenshots because it seems  that everything is clear.

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