Hair And Depth Of Field

[GazzaMataz 12]

I have asked this before (I think) but my post has dissappeared (probably since this forum has been re-vamped). Anyway I have been working on a big project lately which required DOF. Now using AR as I do most of the time it works fine with most objects except hair... And alpha channels. If I render a hairy object with DOF the edges go blurred. Physical render works but is SO SLOW! I have tired to use Object Buffers but they don't work with hair either. I know that I can select the hair object and under the 'Generate Tab' and change the type from 'None' to 'Circle' but I was wondering if ther was another way to fix this or does R21 have a fix? I haven't tried R21 yet but I dare say that still hasn't fixed the problem.

 

Same problem with using alpha channnels and DOF in AR, you get all sorts of artefacts where the transparenccy should be...

[Cerbera 3,313]

No, if we want to have DoF with hair, you would have to use the physical renderer (which only works because the hair gets auto-converted to geo). This has not changed with R21, as you rightly guessed

 

CBR

[cendrick 1]

I know it’s not what you asked with using AR, but would Octane help you in this case? I’ve used hair with dof with no issues from what I can remember.

[Fastbee 235]

Octane, Cycles both would fix this problem and render the scene many times faster given you have a decent video card.  This works because of the way the render engines get hair in there.  I believe in Standard Render of C4D the hair is something added in post.  Changing the hair in the generate tab to a flat poly, triangle, or circle would force it to get that geometry in there before post thus having the post post dof work on it.  In Octane and Cycles they have the hair in there like geometry, but the geometry is generated before the render starts so it works.  At least that is how I imagined it working.

[DasFrodo 239]

6 hours ago, Fastbee said:

Octane, Cycles both would fix this problem and render the scene many times faster given you have a decent video card.  This works because of the way the render engines get hair in there.  I believe in Standard Render of C4D the hair is something added in post.  Changing the hair in the generate tab to a flat poly, triangle, or circle would force it to get that geometry in there before post thus having the post post dof work on it.  In Octane and Cycles they have the hair in there like geometry, but the geometry is generated before the render starts so it works.  At least that is how I imagined it working.

 

Yeah, that's exactly how Octane does it. It generates geometry before rendering, which is why a huge amount of hair takes a huge amount VRam, which is an issue in some cases. Coincidentally I've been playing around with hair in Octane yesterday, just to see how well it looks and how fast it renders, even with DoF.

 

This is the result:

 

Nothing fancy but it might give @GaryAbrehart an idea of how well hair works in Octane. It's dynamic as well, so you can render full simulated animations with it.

[GazzaMataz 12]

Thanks for the replies peeps. Looks like I will have to switch to Redshift at some stage to fix this since I have a Redshift licence.

Thing is I have one render heavy project a year and to complete it I need two machines so that would mean buying another computer with at least two GPUs in it to create the same workflow and that would mean at least a £2k expenditure (not including the extra licences) and I am not sure if the project will return since I do it every year.

One other thing is AR doesn't seem to like alpha channels either and creates nasty looks when using DOF I imagine this is the same problem as hair so Redshift should fix this too?

[DasFrodo 239]

You could just rent hardware or send it to a renderfarm. There's renderfarms for Redshift I think, only Octane seems to have this thing where they only allow their own renderfarm because of some licensing stuff. No need to buy new hardware just for that.

One service I have VERY good experience with is https://us.rebusfarm.net/en/lets-go/render-farm-specsRebusfarm.

They have a dedicated Plug-In that is basically one click and you render your scene. They are also very affordable.

[GazzaMataz 12]

@DasFrodo

I have used Rebus in the past and they do a great service and support Redshift. The problem that I have though is I work on short animations usually between 10-30 secs. Now I normally render out a low res version send it to the client and whilst that is rendering on my second computer I get on with the next one and it works very nicely, although HD version take a lot longer. Usually there are 2-3 versions until the final version is signed off and ready for HD output so you can see I am rendering a lot for each animation. This can add up and eat into costs which means my returns are low. Not only that I use Xrefs on almost every animation and Rebus doesn't accept Xrefs so I would have to convert everything every time for render which can be time consuming. And I would be able to use the converted versions since the Xrefs might need changing. So it is a bit of a pain…

[DasFrodo 239]

Well, the question is, is Rebus ultimately costing you more money than the new PC? I mean yeah, you can use the PC lateron as well but do you need it?

[GazzaMataz 12]

@DasFrodo

That's the million pound question And I would probably only use the machine for this particular project which comes up once a year.

 

I calculated that if I was to use Rebus for the project it would cost me approx £500 in render fees each time so weigh that against a new computer at £2k and I would get my money back after four seasons... Seems like a no brainer from that ponit of view.