Digital Art Zone

Some months ago, I purchased the reality 2.0/luxrender package.  Fired it up once and just thought it was way over my head since I had used to ol’ point and click firefly and 3Delight renderers.  So, today, thought I’d take it for a test drive since I’ve educated myself in the actual nuts and bolts of renderers a bit.  What I’d like to know is it common for a basic 1-light portrait/head-shot render, 1584x2000 pixels to take 28 HOURS to render?  I’m looking for about 500 pixel samples before I shut the renderer down and it’s taking about 2 minutes per pixel sample.  From what I can tell from the status bar, I’m running between 10 and 14k samples/sec.  I’d really like to re-render a few of my favorite scenes with reality but at that speed, it’ll take me weeks for just a few renders.  Any help for speeding up reality/lux would be much appreciated.

The image will keep rendering until you hit stop.

Reality, or more correctly the Lux render engine, never finishes a render, because that isn’t the way it’s designed to work.

Lux starts by rendering a very rough approximation of the scene. It then refines the render to produce a more refined image, and keeps refining and improving the render until you tell it to stop. Watch the image, and when you’re happy with the result and can’t see the incremental changes, stop the render.

Without your system specs it is hard to judge if its being slow or if your computer is dragging it down.

Reality (Lux) is significantly slower (in my experience) than for high quality stuff than the native render engines in DAZ/Poser though, thats the trade off for the more realistic images.

500 samples/pixel should give adequate, or even good, quality - if it isn’t, is you scene enclosed in a room or environment that might be blocking the light?

we need more information like the system specs and and maybe the image itself.

Also 30 hours to render is not that long frankly. You can always cut the resolution down if you only intend to use the image on the internet. If you cut the resolution in half,  700x1000 it would take approximately 7 hours (based on your initial statement 28).

There are people who let there renders run for weeks, it depends on your system specs and how many samples the image really needs.

I often have to leave mine running till they hit 1k S/P or more.

one thing I have not figured out is why some renders take longer than others even though they seem like they should be about the same setup. I had one render take 40 hours, while another scene with similar setup took 8. Once I figure out the variable I’ll be a happy camper.

If you have other computers on your network that can contribute to the render I would do that. Lux lets you add other machines to the cluster, so you can save time there. The hold up will be ram, each machine will need to have enough ram to hold the scene otherwise it won’t work. By adding a second machine I cut my render times in half. So that 40 hour render was originally 80 hours for something that was 2400x3600 or so.

I believe Paulo said that Lux calculates everything in a scene including what is not visible within the frame of the render.  Render times will speed up,  if you remove or make invisible anything that is not in the “shot” .  Also glossy surfaces take longer to render than matte.

Hiding unseen things body parts and grouping lights dont really do much IMO. Its all depending on whats in the scene. I have been at it for 3 months 200 plus renders. I get anywhere from 40 minutes to 3 days.  I have discovered what seems to eat alot of time is a large amount of lighting.  Do keep in mind that new new LUXRC’s seem to render alot faster..

I would also recommend experimenting with the hardware rendering option if you have the video card for it. You don’t have access to all the surface options if you do pure-hardware rendering, but with a good videocard it’s quite fast.

Hybrid hardware-software mode can improve performance in scenes with lots of glossy surfaces, but will reduce performance in simpler scenes due to the extra overhead of co-ordinating the two systems.

Bobvan - 14 June 2012 12:49 PM

Do keep in mind that new new LUXRC’s seem to render alot faster..

I think I have noticed about a 50% increase in speed as well with the most recent RC, really impressive.

I find I get much superior results with LUX. I dont modify maps and such. I switched to LUX was because I could not be bothered with tweaking too much stuff. Its kind of like with a computer. Some will overclock modify motherboards ect. I Just want to set up and render. The film response and settings in LUX work really well.  And finally for stuff that will not play nice in LUX.. PS is your friend…

OT Im finally starting to get LUX commission project for which I can now charge more for more time invested..

OKay.. machine-wise.. I know I’m a tad slight in the ram department.

It’s a quad core amd phenom 9600 gt running at 2.3mhz, 8 gig of ram(can’t do anything about it until october).
As far as letting renders go forever.. just can’t do that at this time either.. need the machine for school which involves other 3D rendering at times.  Since originally posting this, I’ve had some pretty amazing results with SLG.  I’ve also talked a bit and harvested tidbits of information here and there.  One thing that was slowing my renders waaaaaaaaaaaaaay down was having DazStudio lights in my scenes.  I’ve taken them out with better results.

Where I’ve decided most of my roadblock is is more mental than anything and a product of my artistic past.  I started out in the irc-based magazine scanning community.  Mainly on the dalnet channel #SDC for those who may know of the irc community.  The way you work with magazine scanning is to scan huge, do your post work and then reduce image size to tighten up the image.  It wasn’t unusual for me to scan at 900 dpi which creates an image well over 7000 pixels high for a full page scan and then gradually reduce down to 72 dpi which makes a respectable 1024x768 shot.  I still have(had) that mentality with rendering.  Render huge and reduce in postwork.  That isn’t needed with most renderers and specially not Lux.  I have to put it in my mind to render at what I want the final size to be or just a wee bit larger.  This would greatly reduce my render time but it’s hard to overcome as I’m used to looking at really high quality pics that are like 3000 pixels on the longest side.

On the lux side.  I’ve downloaded the 1.0rc version and installed it but reality still is telling me that it’s 0.9 and I can’t seem to find out what the issue is.  I’ve even installed it in a separate folder and pointed reality to the new folder.  I’m using reality 2.0 and can’t do much about upgrading to 2.2 until October either.  All my rendering product was provided by my now-former employer and I don’t have the info to get the free upgrade to 2.2.  Fortunately enough, content-wise I was able to walk away with all the product that I had purchased for the company going clear back to ‘06.. which if my math is correct equals up to the cost of a new Corvette with all the options.

Haven’t had the time to render with Lux after harvesting the new info that I have in the last 24 hours; but, I’ll post the results later when I have something to show for my work.

I only have 8 gigs of ram and I make it work, but then again I know I can’t render higher than about 4000k pixels in a single dimension. usually renders start off eating around 4g and slow go up from there. Haven’t had a problem though. I do want 16gigs, but I can’t really do that at the moment so I just work around it.

And a lot of my scenes end up only needing 2gigs of ram and occasionally less (a pinup for example).

Glad you got rid of the daz lights