WHAT IF: You NEED that render done in 2 hours!!!

[danb4026]

and you had 3 options to cut down the render time, but maintain as much quality as possible, would you:

 

1: decrease image sampling?

2: lower GI settings? or;

3: lower image resolution?

 

You can only choose one, and why?

[Claudio Branch]

I would probably just drop the GI settings and then hit that baby with the Unsharpen Mask in Photoshop.

 

I've even done it with Scanline and it worked well...

[danb4026]

I new some good tips would come out of that question....good start! Thanks Claudio.

[Crazy Homeless Guy]

I guess I would need to know what resolution you are rendering at. I might drop that, but not below 2500, unless it is only going to be projected.

 

Also, I would need to know what type of scene it is to know whether not dropping the GI is a valid solution. If it dusk or night with a lot of lights, then dropping the GI quality may create a whole new set of headaches with light leaks and the such.

 

As for the sampling, drop it for a quick render. I would rather have better light than a perfectly sampled image. The light is what makes the rendering. The sampling makes it look nice, but maybe at the highest price.

 

In reality, I would probably do a combination of all three. The more rendering you do, the more you know exactly how to speed weak your image to get the most bang for the buck.

 

Other things I do in crunch time, or to prevent long renders in general...

 

- Adjust the sampling on individual materials, this can greatly reduce render time. You probably know of a few metals in your scene that are hogging samples, that can be adjusted if speed is needed.

 

- Render glossy or reflective surfaces in a separate pass. This will save a great deal of time. This is useful for floors.

 

- Turn on interpolation if you can get away with it.

 

- Turn off opacity maps and cutout mapping if possible. Sometimes a well made diffuse map can simulate things like perf metal well enough to fool the eye. It all depends on the situation.

 

- Make complex objects or objects with lots of glossies not visible to reflections.

 

- Lower the reflection and refraction bounces. You can always patch render a spot in with higher if they are good for most of the scene, but only bad in a spot or two.

 

- Precalc a light solution, and the strip render the image.

 

- Use a simple, one sided glass, rather than a physical glass.

 

- Turn glossier metals to render as highlights only in the reflection rollout. You may not miss a reflection on a matte aluminum as much as you think.

 

I am sure I can think of a few more.....

 

Also, if you drop the GI, you might be able to pull back in some of the detail with a "tight" AO pass. I would avoid the loosy goosey ones though. They majority of the time they just make your image look muddy or bring back memories of scanline with point lights.

 

You might also try to have things like 3d trees pre-rendered on their own layer. This way you can drop lower res ones in the file that are not visible to camera. This way they still cast shadows, but don't require as many system resources. I often do this with 3d cars also. Render out nice ones, the drop matte version in place that are not visible to camera, but still cast shadows.

 

All in all, sampling and glossies are the biggest culprits when it comes to slow renders.

Edited August 11, 2009 by Crazy Homeless Guy

[danb4026]

OK, let's say you were originally set up to print a 8.5x11 at 240dpi ( I don't like to go below 240dpi for presentation), so that's around 2600.

[FreakiestFish]

This is what I might do:

 

1. Exclude small objects that does not required reflections and refractions

2. Reduce unnecessary light sources or add illumination in texture to reduce light source.

3. Lower GI setting

4. Render in 16bit multi-pass and touch up in Photoshop

 

With 240Dpi, I assumed it would only bring down the render time marginally unless it is a network rendering.

[visual3d]

A faster computer. Borrow or get someone to do render it. You have work hard on it only to discover you dont have time to render. Why waste the quality job...id say loose some of your fees to someone for rendering it..

[SandmanNinja]

Submit it to a render farm?

[JonRashid]

I would split my model up into the parts that require GI and those that dont. Then render all vegetation etc with normal non GI light settings and use re composite. You can just apply a matte shadow to all other objects as re-render

[danb4026]

In response to the "render farm" and "faster" computer option.....NOT one of the choices!!

[erickdt]

Are you talking about rendering 1 view or a series of views?

 

Also, to me, 240dpi is excessively high for printing. I usually do 150dpi, 200dpi if I have the luxury of time. 150dpi usually looks pretty good though.

[Nic H]

always do a lower res, much faster

no one really cares, and architects dont really understand much.

 

for ages (depending who i was working for aka shitty money jobs) i would render real small and upscale with fractal enhance pro or whatever its called because my home workstation was slow and the jobs were somethign i was ever going to show anyone.

 

granted this was for the kind of people that when asked for a pdf of a logo would just save the jpg as a pdf.

[danb4026]

I am talking about a single view.

 

I also print a lot of 11x17, which at 150dpi is also about 2600. So an 8.5x11 @ 240 is about the same as an 11x17 @ 150. So lets call 2600 the number.

 

I am also not talking about images that you don't care about. I am referring to presentation quality images. Most of my work now is for developers and design architects presenting their designs to developers. They want their designs to look as good as possible for presentation, but they are always on a deadline as well. For them, it is important that individual materials show well and that the lighting design is well executed.

Edited August 11, 2009 by danb4026

[BrianKitts]

always do a lower res, much faster

no one really cares, and architects dont really understand much.

 

Got to agree here... it's amazing the absurd sizes that I've seen people blow up low res images to, without even realizing that it looks bad. (makes me cringe)

 

But that being said, it's also entirely possible to render to a lower res image, and get a pretty good image when upsampled with a program like genuine fractals.

 

so that's my choice > #3

[danb4026]

I am not familiar with Genuine Fractals. I have used a Photoshop plugin called Re-sizer, but haven't really been happy with the results. Could you expound on the program and its features?

[Crazy Homeless Guy]

I have mixed feelings about Geniune Fractals. I have never got the results shown on there website.

 

If you render low, I would first try ramping your image up in Photoshop. Then throw a bit of unsharp mask on it. You are likely to get just as good or better results than genuine fractal.

 

1500 pixels wide, then 1600 pixels wide, then 1700 pixels wide, and so on. Make sure to use the algorithm for enlargement in PShop.

 

But I still believe the speed of you rendering lies in the sampling of your image at both material and global level.

 

Also, in Vray, try setting the AA filter to none.

 

Hardware upgrades aside, please tell me you are using at least a quadcore?

[danb4026]

Personally, I have an i7 920 and 12GB ram.

 

But the purpose of this discussion was not to talk about hardware, but to learn from others what methods they use, everything else being equal, to get the most bank for the buck ( and I don't mean $$) with render settings given a time constraint.

Edited August 11, 2009 by danb4026

[erickdt]

That must be a pretty complex scene to take more than 2 hours to render a single view. If I were in that situation I would have to step back and re-evaluate how I set up my scene. Are the effects (glossy effects, caustics, DOF, etc.) that your using worth the extra render time when it comes to the final output? Also, I would check to make sure my subdivisions on materials and lights weren't excessively high. I rarely use subdivisions more than 12.

 

*Keep in mind that it is average Joes that are viewing your output not your fellow CG Artists, what might seem "cool" to you and I might not even be perceptible to them.

 

If my scene takes more than 30 minutes to render a single view at full output resolution (which is usually 2550x1913) I generally think that I have a problem with render times and the scene needs to be better optimized...

[Crazy Homeless Guy]

Sorry, I am using MR these days, material samples in MR = material subdivisions in Vray.

[Chad Warner]

Speaking of enlarging images, I saw a link for this the other day:

http://lifehacker.com/5330199/smillaenlarger-enlarges-your-images-without-artifacts

I haven't tried it yet, so I can't say how well it works or not, but I thought it was at least timely to the conversation.

 

I will also generally upsize images if I know someone is asking for an absurd resolution that I know is overkill....we just did a billboard that was to be 8'x40' and the printer wanted 200 dpi. 19200x96000 pixels. I Just told them sure, and then proceeded to double my output resolution.

[danb4026]

Chad, how did you double your output resolution, PS?

[Chad Warner]

Yeah. I made an action that resized in 3% increments and just ran the action until It was slightly larger than I needed it, then scaled back to the final output size. I wouldn't ever do this for most scenarios, but I know that 99% of the time a billboard of that size doesn't need to be any more than 25 dpi.

[rgb]

I would try to balance all 3 options really,

a bit of compromise on resolution, little decrease in image sampling and just enough GI.

[danb4026]

In talking about materials, and specifically, glossy reflections, I have a number of materials that I accumulated from vraymaterials.de. Many of these materials from woods, metals, plastics, etc have glossy reflections and subdivisions set to 32 and higher.

 

Is this generally way overkill? Erick just stated that he rarely goes over 12.

[BrianKitts]

I leave everything at 8 unless I notice something in the rendering, in which case I turn it up as needed. but still thats normally only around 15-20, I've don't remember ever needing to go higher than 30 which was on a realistic stainless steel shader with anisotropic ringing