Set up a scene yesterday, set it to render overnight as I expected it to take a few hours. Got up this morning, still rendering. Finally finished after 11 hours and 55 minutes.

The main culprit was a hair figure (Goya Hair for M4). Rendering that in a scene with IDL, multiple lights and 3 bounces took forever. I rendered the scene (from a different angle, where the hair occupied less 'real estate' on the image) and made the hair invisible. Rendered again, took just under 2 hours.

Tried then doing an area render of the hair with reduced settings, but after an hour had barely done 100 pixels in the precalc indirect lighting pass, so...

cancelled the area render, went to D3D's firefly render settings, changed to progressive render, set samples to 12, then used area render again. Half an hour later, it's done. The artifacts are invisible because of the type of hair figure it is... basically the thing that caused problems for IDL are what let me get away with this using progressive. Had I done this for the previous scene, I'd have saved myself roughly 5 or 6 hours. I still have to merge the 2 images, but that is literally 2 minutes with the eraser tool...

Might come in handy for someone...

 Hi,

You can disable light emitting for the hairs and increase the shading rate.

But in general FireFly is not a "lightning war ", all my renders took between 6 and 12 hours, i click "render" before going to work, when going back home render is finished ;)

I might try that one today... cheers!

 Hi,

You can disable light emitting for the hairs and increase the shading rate.

 

But in general FireFly is not a "lightning war ", all my renders took between 6 and 12 hours, i click "render" before going to work, when going back home render is finished ;)

you really don't want to disable light emitter for hair as I pointed out in this thread (with examples) http://www.renderosity.com/mod/forumpro/?thread_id=2890237&page_number=2#msg4204376

if you turn off lite emitter, posersurface doesn't participate in IDL bounces. if it's hair where only single (outside) surface visible in render in typical empty poser scene, then lite emitter wouldn't matter, but if it's got multiple complex surfaces or is in fully-populated scene, lite emitter would matter.  maybe they speeded up hair render in PP2016 so users won't turn off ray-tracing any more.

 @ghostship2, you show only render quality (with a little work with node you can have good shader without sss) the thread is about accelerating renders, sss isnt the best way ;)

Now two fast renders, shaders on hairs (Ricardi from neftis close to the Goya) is not modified, left hairs emitt light, right hairs dont emitt 

 30 seconds, nothing you tell me, now imagine a complete scene with a high end render setting.

Just for the fun, without light emmiting and shading rate from 0.2 to 1, render take 1:21 so i win 20 seconds.

Total i win approximately 57% of the initial render time, just by modifiying two parameters 

I don't have that hair piece to test myself but it looks a little "off." Blurry, and wispy in places. It is also a dark brown instead of blonde. The point I was making in the other thread was that I almost always use SSS on long flowing hair, especially if it is blonde and I needed a new machine to help with that. When you start having hair that surrounds the face, you need it to be a light emitter, otherwise strange stuff starts to happen.

Goya hair is short and curly (sorta). Light emitter on or off makes little visual difference although it may well be scene lighting specific. Render took 5 hours 11 minutes, so rendering him bald (2 hours) then rendering his head and hair using progressive with 12 samples (maybe 1 hour) is still miles in front. Again, this is specific to the type of hair where the little speckly artifacts won't be noticed.

I have Neftis Beautiful Black hair which is kinda the same except longer. Huge amount of single small curls. Takes forever and a day to render...not sure if it's the number of strands or the poly count that makes it so slow to render. I would have trouble merging a hair piece like that and a bald head in Photoshop. I usually only do that with hats where the hair pokes through.

Not all that difficult... I end with with the initial IDL render with character bald, and a second area render in progressive mode over that (so the basic frame is the same, you just get that annoying white 'drop shadow' line) with the hair included. In Photoshop, copy/paste the second render over the first. Take eraser tool, soft edges, run around the hair and clean up the now spotty face. Done in 2 minutes.

Again, it is scene/lighting specific. There would be some scenes where a more complex extraction method might be needed. It is still saving me hours.

Here is an example of the BBH. This render took my poor little i5 about 3 hours!

 Hi

Some tests ...

Hair with defaut shader and light emmitting -> render time 6:52 

Second picture, modified hairs shader and no light emmiting -> render time 1:51 

 That's all ;)

The second one with LI off looks flat and cartoon-ish. I used the default hair settings as well. Your render setting and lighting are flattening the image out as well. I still would rather spend the 3 hours rendering than 6 min and flat results. :)

 It's not a good render i agree, i just show how to reduce render time

cool!

Shading rate shouldn't matter too much on complex polygon transmapped hair models. They have many angles and vertices running around in them, most of them bending far above .2 relative to each other, so if you bump the shading rate up a bit, it shouldn't make a huge difference. (Individual mileage may vary. Hair with very subtle bends in it, like long, straight, hair, might need lower shading-rate settings to pick those differences up.)

Light Emission is the killer. For me, I don't see the need in making most hair an emitter. Why? Because, it's all fairly unrealistic anyway and with closely bunched up polygons, many times intersecting each other, it's an effort in futility that yields little in the way of meaningful results. A good material set can take care of just about everything you'd want, anyway. And, a very good transmap, too.

I finally tracked down the problem with the Goya hair... a bit embarrassing really...

ambient had been set to zero, but one texture layer had an active translucence channel set really low... so the hair glowed a bit. complex polygon hair bouncing its own light around among itself... no wonder it was taking hours. Removed that channel, hair renders at normal speeds. 'Doh!

The second one with LI off looks flat and cartoon-ish. I used the default hair settings as well. Your render setting and lighting are flattening the image out as well. I still would rather spend the 3 hours rendering than 6 min and flat results. :)

Really?  You people have great eyes.  The second image had curls that looked crisper.  You could see individual hairs rathers than having them blurred them together.  Perhaps it's just my eyes.  The skin and everything looked about the same to me.

Still a good thread.  Anything to get a faster render.  If I render large, say 3170 x 2244, I set it up to render just before I get some sleep.