options for faster rendering?

[Ernest Burden III]

I am wondering what ways there are to get faster renders (especially for animation frames, or course) from C4D 8.5

 

I have been running some test sequences with various radiosity settings to see what works to my liking, and have been happy with the animated results (what flicker?). But the one that I like the most--stochastic with low settings--is taking FOREVER to render. I started a 3 second clip at DVD res and took my son out to do do some things. The boy is worn out and napping but I'm only through 1/2 of the frames. No good.

 

So aside from any settings, is there a better way to render than just 'render to picture viewer'? In Lightscape I just use a command-line window so its 100% outside the GUI, and a LOT faster. Is there something similar in C4D? I could use networking to add two other machines, but I'm first looking at single-machine solutions. Ideas?

[jackb602]

Ernest,

 

Stochastic mode can be very slow. The radiosity tutorial here explains very well how different settings affect quality and render times.

 

I've also found that glass materials can often kill render times. If your scene has a lot of glass, try a test render with all glass turned off. You can then fine tune the shader to get faster results. A high Relfection Depth setting can really slow things down.

 

The brute force solution (if your budget allows) would be to use a render farm service like Render King. I'm sure others will have more advice.

 

Jack

[Ernest Burden III]

The radiosity tutorial here explains very well how different settings affect quality and render times.

Jack

 

Thank you for the link, it looks VERY helpful. I will study it in detail later.

 

I've also found that glass materials can often kill render times. If your scene has a lot of glass, try a test render with all glass turned off. You can then fine tune the shader to get faster results. A high Relfection Depth setting can really slow things down.

What I have as my benchmark is this, as rendered by Lightscape (this is full-size):

 

 

which I processed in Photoshop to yeild a final of this:

 

 

The raytrace from Lightscape took, on average, less than 4 minutes. Some frames took closer to 2 minutes per, though I do not remember where this one falls in the range.

 

Am I going to be able to get comparable speed out of C4D on the same computer?

 

But to be more clear about my question--is there a better way to render frames than the GUI-based render?

[jackb602]

Ernest,

 

I don't know of any way to render in Cinema without using the GUI. Regarding your reference scene, I can't give you a meaningful estimate of how long it will take without knowing more about the geometry, lights, materials, etc. One way to speed up the GI calculations is to exclude objects from it that don't have a big impact on GI. For example, your railings have very complex geometry, and your furniture will contribute very little to bounced light. To exclude them from the GI solution, add a compositing tag and uncheck the "Seen by GI" box.

 

I almost forgot another option. If your camera is the only thing you're animating, use Single Animation Solution in the GI settings. This will calculate GI once, and speed up the rendering of individual frames.

 

Jack

[Frosty]

Ernest, I just finished a large animated project. I cant show any of it yet, but hopefully soon. i used Cinema's network rendering package to solve my issues. I'm not sure which package you purchased or what your hardware situation is but Cinema has a network rendering package called NetRender. It ships with the XL bundle in a 3 client license format (you can use one machine to host server and three machines to crunch frames). Upgrades are available to this license including a 10 client license and an unlimited client license.

 

I purchased the unlimited version and am now pushing about 50GHZ of processing power. Zoom zoom

 

With this set-up, I was able to render approximately 8000 frames in a little over a week.

 

So thats the brute force method. Of course you have the option of working more efficiently.

 

Stochastic mode, and I agree it looks better, calculates the GI solution on the fly for each frame. Standard GI mode can precalculate the solution, save it, and then render all frames using that solution. The end result is a much faster render. However, there are caveates. The GI solution must be calculated and uploaded to the server with the model and textures. Calulating the GI solution can take a long time. There are also a few other options to set in regards to using the saved solution, I cant remember what they are off the top of my head.

 

Anyway, I hope that helps a bit. If you are caught in a bind, gimme a shout and perhaps we can work something out for use of my farm.

[Ernest Burden III]

Stochastic mode, and I agree it looks better, calculates the GI solution on the fly for each frame. Standard GI mode can precalculate the solution, save it, and then render all frames using that solution. The end result is a much faster render...There are also a few other options to set in regards to using the saved solution, I cant remember what they are off the top of my head.

I guess a saved solution is best for speed. I can add noise later, as usual, but the stochastic mode does it for you, and better. But I do not need a re-calc'ed solution for each frame. That would be useful for a few things, like when lamps must move in space, or a large, important object must move, or a moviehouse with a playing movie lighting the space. Other than those, using 'exclude from GI' on moving things like cars would be fine.

 

The reason I ask about a commandline option is that rendering out of Lightscape in a DOS window is a LOT faster that rendering from the GUI, all settings being the same. I had hoped for the same in C4D.

 

Thank you all for the replies, it is helpful. And I do not have an imminent need to render frames. I am using between-project time to learn a new tool.

[Frosty]

If you bought the XL bundle, you should really try setting up a small farm. The render client is close to a command line app - its kinda like SETI. The entire set-up is quite easy to implement and operate.

[Ace_Face]

Ernest,

 

To answer your question about speed issues with command line rendering or (rendering to disk) being faster than rendering to the picture viewer. We have an unlimited Net Render license at our office and I render single frames to Net render all the time in order to keep my machine free for working. I just "save as project" and transfer the file to the Render Server and start the rendering using the web interface. Essentially that is the same as a render to disk or command line render. There is no speed difference between that and rendering to the picture viewer.

 

I consider this a plus because Cinema 4D doesn't punish you for looking at the rendering as it's being calculated. This way you can do test strips using "Render selected area" on your scene to check lighting and materials etc.

 

Here's a rather useful Radiosity Settings Chart that I found in the tutorials section at C4D Portal. This should help to target the settings you want a bit more quickly.

 

Additionally in the Advanced Render manual there is a section that describes the best minimum & maximum settings based on the image size. You should check that out as well.

 

PS. That's a beautiful scene you posted up there.

[STRAT]

i dunno about command line rendering in c4d :/

 

i used to do it in 3ds, but didnt really find that much speed increase. you could try batch rendering. i do when i have several stills to render over night. dunno if it's faster tho.

 

Stochmode rendering is great, but as you say, freekin slow. i never use it. i use standard gi mode with accuracy set to 100 or 95% plus.

 

also use the camera animation technique. you can either pre-cache a gi solution or render first time only.

pre-caching is faster, but not as accurate and prone to 'flicker' more.

 

so set to camera animation mode, set all your other settings, set to First Time, then hit render.

 

the animation automatically pre-saves it's own gi solution off the first frame, then uses this solution during the pre-render for the other frames.

 

Also, these are my general tips to speed up render times -

 

1) gi accuracy - entirely up to you and your processing power.

 

2) prepass size - i religiously use 1/3. a nice 'in between' size giving no noticable quality drops, but faster pre-render speeds.

 

3) diffuse depth - again, i religiously use 1. a zillion times faster than 3 (and even 2 in most cases). i find 1 is a more realistic lighting bounce, and if i need more light i subtly add a infill omni or 2. muuuuuch faster, and just as real.

 

4) stoch samples - again, scene dependant. with large flat open faces a high sample rate (together with higher min samples) is needed.

Personally, for my 100% accuracy gi renders, i like to use a stoch sample rate of 300ish

 

5) min res - suck it and see. for general architectural scenes i find 30ish does the trick.

 

6) max res - the more straight edges the more you need. i generally wont go higher than 200. (again, there are further tips to minimise this, but it gets complicated )

 

7) render tags - use these as much as possible to limit gi recieving/casting properties on objects. i mean, why have glass giving and recieving gi, invisible isn't it?

 

if i think of anything else i'll post it up.

 

i'm getting lazy these days - since my new pc's arrived i cant be arsed with optomisation much

[STRAT]

another vital render speed tip which didnt really hit home until recently -

 

what really takes up the render time, what i found reeeeeealy slowed things down in recent long renders, was not the gi or gi settings, but the reflections.

they took bloody aaaages. even after i fiddled with the reflection threashold, the ray depth, turned off gi cast/recieve to refs and turned the AA down to 1x1,2x2.

 

just something to bare in mind. make an effort to optomise all the scene's reflections before long rendering, else it'll take ages.

 

oh yeah, if you can avaoid it dont over use SLA, another drain on the speed.

[Ace_Face]

what i found reeeeeealy slowed things down in recent long renders, was not the gi or gi settings, but the reflections.

they took bloody aaaages.

 

You're right Strat. In fact Maxon recommends using a compositing tag to remove reflective materials like glass, mirrors, etc. because of both the slow render times and the fact that they don't contribute much to the GI solution.

[Ernest Burden III]

You're right Strat. In fact Maxon recommends using a compositing tag to remove reflective materials like glass, mirrors, etc...

You mean remove them from the GI? Can't that be done with the material settings, just uncheck GI and caustics?

 

Thank you all for the info, by the way.

[Ace_Face]

This is an excerpt from page 10 of the Advanced Render manual. The way it reads is that you would have to remove GI from the material settings and with a Compositing tag. I think it should really sat that you can remove it from either location.

[Ernest Burden III]

Yeah, at the end it does say "doing these both will..." so both?

 

I will have to get used to the tags thing.

[STRAT]

ultimately, the material's individual illumination settings determine the absolute gi for a material. turning the 'generate gi' to off will stop the material GI being cast, but adjoining objects will still recieve gi from the object itself, but not the material. turning 'receive gi' up or down is the best control for a material's gi setting.

 

the composite tag 'seen by gi' setting on/off is slightly different. by turning off a material's gi in the composite tag will convince the gi calculation that the material and object completely dont exist where it comes to casting gi.

 

but for instance, if you have a skylight in the scene these objects will still recieve gi. most usefull for glass and semi opaque materials.

 

kinda gets confusing. somewhere where maxon need to work on i think. take some experiments to look see.

 

ultimately, even tho a combination of comp tags AND material illumination control should be used, i find a material's 'recieve gi' the most flexable and controlable.

[Ace_Face]

Thanks Strat!

 

Your explanation is clear and concise. I now understand the differences.