Lighting problem UBERNOOB

[ZAPZ]

C4D Version 2023.1.3
This is my first C4D project and very new to 3D graphics in general. Theatrical and Videography background, using Adobe Pr, Ae, Ai.
Making School Crest 3D. Animating various effects
Created a scene with back, side and top lights
Saving MP4 with Alpha to make a Track Matte so the final video has transparency and can be overlaid onto any background.
No problems with basic color materials but when experimenting with some metallic and glass effects I am having trouble. See Photo's
As soon as I put a Physical Sky in, no problems but then I can't get the transparency?
Obviously I'm missing some basic principal. Had a quick look for tutorial. Any help or direction to an appropriate learning resource would be greatly appreciated.
All examples are the same lighting and camera position except the obvious addition of the Physical Sky
Cheers,
Zappa
Ravo Crest Materials.c4d

[Dr. Sassi]

Hi Zappa,

Your project file had only materials in it. So I added a Capsule and a Torus.
The file was set up with Standard Render.

You need to use an Object Buffer for the parts that need to be in a mask.
An object buffer can be applied with the
Object Manager> Tags> Render Tags> Compositing Tags

Compositing Tag
https://help.maxon.net/c4d/2023/en-us/Default.htm#html/TCOMPOSITING-ID_TAGPROPERTIES.html?TocPath=Object%2520Manager%257CTags%2520Menu%257CRender%2520tags%257CCompositing%2520Tag%257C_____2
Compositing tag> Object Buffer
https://help.maxon.net/c4d/2023/en-us/Default.htm#html/TCOMPOSITING-COMPOSITINGTAG_GROUPOBJBUFFER.html?TocPath=Object%2520Manager%257CTags%2520Menu%257CRender%2520tags%257CCompositing%2520Tag%257C_____4

Sadly the newer version of the Help misses that page.
https://help.maxon.net/c4d/r21/us/index.html#DRENDERSETTINGS-RDATA_GROUP_MULTIPASS

The Render Settings> Multi Pass> need to have Object Buffer Passes. Those can have numbers and the Object Buffer ID.

An Object Buffer with a specific ID can hold one or more objects.
An object can appear in many Object Buffers.
The ID of an Object buffer can be greater than 12, up to 10000.

I would advise using image sequences to create content for composting. The mp4 format is not based on single frames and should be used for delivery. For compositing, you need to go with something that allows you to store information per frame bases, preferably without compression.
Alpha Channels and Buffer are information-based, not images based. That way, storing them in a Gamma-based and compressed format would take much of the quality out.

All the best

CV4_2023_drs_23_REob_01.c4d

[ZAPZ]

@Dr-Sassi Thanks for your quick reply! I think i'll need to pull this apart and do some more experimenting before i get the required results.
Still confused as to why the basic materials are visible when i place lights but the metallic and crystal ones aren't?
Anyway i keep trying to learn when i have the time. Unfortunately it's a very small part of my work.
Cheers!

[Dr. Sassi]

Hi Zappa,

Yes, there is always too little time.

My suggestion to help that a little bit, keep asking questions. Besides that, set up small scenes and render privies in Stamp size. The primary stop in learning is a slow response from your "machine"; no matter the speed of your computer, it is always slow when it holds things that don't matter for that moment. I understand when little time is given, one like to have at least one thing rendered out as a reward.

A good mix is the best approach. Just a plane object and a sphere plus material and light, one light! Never toss too many things in a scene. A typical mistake is the illusion of progress by loading things in the scene because one has them. (… based on my observation over nearly two decades of mentoring artists)

Keep it super simple. Then explore while rendering in 1/4 of HD or smaller, just enough to get feedback. The more you learn, the faster you will be. No beefy CPU will replace this. (I have rendered as preview three projects this evening in 480x270 to get an idea of the speed and progress of a scene in terms of color and animation. That makes me faster than anyone who always renders as large as possible. I learned that in 2004 from an ILM artist.

The more you get familiar with the mix of parameters, the faster you get where you like to be, and so, the little time you have is better used. Yes, that is a little bit slower at first.

Your question, some materials can be reproduced quickly, but some need more complex calculations. This is all I can say, based on a general question.

Enjoy