L. O. L.
very clever.
It’s not a major priority at the moment. I hope to enable it for use with the triangle primitive modes quit soon (next few weeks) since this should work perfectly fine on the gpu. It will probably be awhile before hair segments work well on GPUs though.
The curves are generated as cubic cardinal splines on the fly. 2^subdivisions gives the number of subsegments. So if you have steps of say 4 (to give 2^4 segments) and 3 subdivisions (8 subsegments) it will probably give very similar results to having 4+3=7 steps i.e. 128 segments. There are differences as the curve subsegments are joined and the normals are calculated differently. Also, the interpolation occurs between the segments points and there still needs to be a large enough number of these to get the basic curve path setup.
If you use 0 subdivisions it gives straight segments. Unfortunately the main slowdown to the method used is at the very start before any subdivisions have been made. Increasing the subdivision number shouldn’t make a vast difference to performance. There is still a tradeoff between memory and performance since curves are slightly faster when more segments are used.
Thanks! very nice test. I am looking forward to see what using children produces.
I kept the children up all night doing this render:spin:
to be honest I like the other one better, this one is too busy
I teach CAD in a high school and have a classroom with 20 nice quad core workstations
Today I used the netrender plugin to render this animation and what takes an hour and a half at home takes 5 minutes there
Renderfarms rock:D
Dave
Thank you for the help, it works now. And I apologize most sincerely for posting it on this thread, wasn’t my intent to post it to the wrong thread. When I posted it, it was real late and I was half asleep. I should have seen this was a “Latest News” thread.
Thank you so much for this great feature! Like everybody else, it’s love at first try. 
Here’s my updated version of my piece titled ‘Aeta’
Oooo I like that 
Thats a really cool hair affect and I particually like the “transparency” feel to the hairs that are out of the DOF focus.
This is so cool! Why am I so behind?! HAHA
I have just fixed some of my mistakes in the curve segments routine. It should fix some of the hair clipping problems when using curve segment/ribbon primitives.
@reynante - Great work! I really like that.
Thanks, @BroadStu.
Are the fixes automatically updated on the builds available from www.builder.blender.org?
-Reyn
They are updated automatically but you have to wait for the latest build to be created. For example builds with that fix are those later than 53935. Currently there aren’t any of these but there should be tomorrow.
Thanks!
-Reyn
haha, this’ll be the second time i’ve updated svn and compiled Blender today, only to get these updates
Hello blender-artists!
this is my first post here. I couldnt find a thread to introduce myself. If there is a thread for this purpose i will do it there and edit this post!
Im a german design-student and im going to do my final project for the BA in Blender.
It will be a short-animation with cartoony characters. Hair is quite important for me, thats why i choosed this thread.
I am not so much into technical stuff. and im just using blender since some month, but it convinced me very well so far! 
Im also very pleased with the render-results of hair in cycles! thank you for that BroadStu!!
I cant complain about something here, just i have some questions which are important for my project:
- Can you allready tell when cycles-hair is ready for GPU-rendering? (is it possible in the next 3 month? or much later?)
- what is the best build of blender for rendering hair? (Im now using the “ming”-build because its faster, i read it here some time ago)
You see, im just concerned about the rendertime of my animation 
Woooawww, real nice feature !!! Awsome !!! Do you have an idea when it’ll be possible to use GPU for rendering hairs in cycles ?
Great works again !!!
Matt
Hjalmar,
No one can say for sure when GPU acceleration will be ready for hair, but I would advise you to temper any expectations you have of it being super useful for animation. If you have a large amount of geometry and large textures you’ll already be fighting against the memory limits of any current GPU, and the number of hairs you would need for a good-looking character would almost certainly push you over the limit.
m9105826
thanks for the advice!
So you’re saying that GPU rendering for hair is anyway not a very usefull feature because of the lack of memory that GPUs suffer compared to the CPU.
It means you have either long rendertimes or you need another solution.
Is it not possible use renderlayers in this case? to render hair and other geometry on different layers and composite them together afterwards? I didnt try it yet…
Hi all,
For my side I have 4 Giga of memory on my cards (2x Zotac GTX 670 4 giga each card). You can put lot of data, and hairs too. It can be usefull to had hair to GPU, 4 giga by GPU is quite enough for some scene and if you use layer to compute high detailled hair and use proxy for shadowing, it’s working. And for the moment, high CPU computing like intel Phi is limited to 8 giga of ram and the cost is 2000€ + the PC… so dual graphic cards is less expensive than CPU solution. Please had strands render to gpu, if possible.
Best Regards,
Matt
Anyways it would still be useful having GPU acceleration for shader tests, because you can’t really evaluate a noisy hair.
Or when you are not using hair, or when you just need only a little of hair.