Reducing Rendering time.

[aloy]

I am not a rendering man, but a certain project involving a large steel structured buildings took many days for the preparation of a walkthrough, couple of years ago. Is there no way of reducing the time?. I understand that this process involves solving of differential equations for reflection of light from various materials in the building etc. Can it not be done through Autolisp instead of going through .NET languages. Common Lisp is also a powerful OOP language. If Alisp cannot do it can Autodesk implement CL and cut short the time?.

[David Bethel]

There are tons of things that affect rendering times.

The big questions would be:

• How large must the images be
• How many frames are you doing
• What would you consider to be an acceptable time limit for each frame

I just finish a project with 2,550 frames @1,536 x 864 that averaged 2 min 20 sec per frame ( 4.5 days ). For me that is a long time in this day and age because I'm used to 20-30 seconds to render each frame. ( The models had tons of glass panels) I could have cut this time in half if I had used one on newer machines, but didn't want tie it up for a couple of days.

Things that can cause render times to increase:

• Highly reflective materials
• Rounded surface or corners
• Too many light sources
• Refraction and reflections settings that are too high
• Background materials that are too detailed

And last but not least, throw as much hardware at the process as you can and keep that machine as lean as possible as far as the number of processes that are running in the background.

I use a larger than required frame size so that I can use a resizing filter as I compile the movie. My final frame size is 1,280 x 720 ( 16:9 HD in You Tube ). It takes a bit longer, but the final results are better.

The stepping thru the path shouldn't be the time issue. So whether its is done thru lisp and any other programming language should take about the same time. I would guess it take 1 second or so to transition from 1 frame to the next. It's the rendering engine. ( I take you are using AutoCADs built in render. )

-David

[ReMark]

Is this (rendering) something you'll be doing often enough to justify the cost of a dedicated piece of hardware?

Powerhouse rendering systems.

http://www.boxxtech.com/

[aloy]

Hi ReMark,
Thanks for the link.
Aloy

[ReMark]

Sure thing. Don't forget to keep in mind what David said in the mean time.

[aloy]

Hi David,
Thanks for the extensive info.
What I am suggesting is a fundamental shift in the way rendering is done. Why Adesk does not try a different approach by changing the technology with respect to the methodology involved in the calculations and using a different language somewhat similar to Alisp or Vlisp which are currently used to run AutoCAD. I do not think .Net languages run AutoCAD.
Regards,
Aloy

[ReMark]

Maybe you're using the wrong program.

[aloy]

From what david said and the link you sent, it appears the technology used is the same. We did the designs of this project around mid 2010 and had a presentation. I am no longer in that office. (I am currently writing from a different country). So, I do not have access to the details at this time. My complaint is why is it so time consuming for Rendering in this age when Americans have technology to land a robot safely on Mars, several billions of mile away. We should be doing things faster on terra firma.
Regards,
Aloy

[ReMark]

I don't do hardware design but if I change fields I'll put your problem at the top of my list to solve. Best I can do.

I still think you need to look at another program to do your rendering.

BTW...what do you have for a computer setup re: hardware? How much physical RAM? What OS are you running? Is it 64-bit? What co-processor is being used?

[David Bethel]

I use old software for that very reason. I render using Accurender 2.0 in Release 13 On a 64 bit Windows 7 machine. For a single image, I make 2,000 x 1,600 images in under 1 minute using just about every option that Accurender can offer.

In my experience, then newer is not faster or better. In fact until 2010 or so, I thought AutoCAD's rendering engine wasn't very good. Hell it takes a minute or so just to get 2012 fully loaded. I'm still not impressed with it's rendering interface.

Have you looked at other rendering packages. Some do very nice renderings. I don't know how they stack up on time and performance.

I like older Accurender programs because it has an API for AutoCAD and I can then automate the process via Autolisp.

-David