Transparency problem when rendering Shave and Haircut in Maya 2013

#1

Hello all,

( I really hope I’m posting this under the correct topic)

I’m working in Maya with Shave and Haircut. My character has several hairsystems going at once and it works lovely. However , in some renders , there is a problem in the transparency. This seems to occur where different hairsystems overlap. Each system has it’s own transparency which works well by itself, however when they overlap, instead of having a cumulative effect , making the hair thicker, it takes the transparency of the top layer of hair and this then cuts a hole in the layer beneath. This doesn’t happen with every render , just from certain angles or distance from camera. I’m rendering the hair in maya software renderer with the hair render mode set to buffer. I’ve tried maya mentalray , but this takes way too long on my machine and creates some weird blocky artifacing. I know many people are recommending the puppet shaders but as I’m rather pushed for time I was hoping that somebody knows of some setting that I may have set incorrectly. I’ve attached an image . The image on the right is a closeup where the transparency is behaving as expected . On the left the hair was rendered from further away. I’ve duplicated the image on the left and circled the problem areas. The only sort of work around i’ve discovered is rendering the hair out separately and then duplicating that layer several times - but it’s not ideal.

Thanks so much for your time, any input would be greatly appreciated.

#2

As far as i know this is common problem with hairs if you use maya software renderer with the hair render mode set to buffer.
How did you try mentalray? There is a way to render fur without raytrace in MR and it could be fast enough. And instead of puppet shaders you can use mentalcore which will make life easier.

#3

Hi thanks for the advice! With mental ray I went into the shave globals, set hair render mode to hair primitives. Render quality is low and compositing is 2d . The "MR force rapid motion " setting is switched off. In the mental ray quality I just selected the Production Fine Trace presets. I’m not the best when it comes to render settings to be honest… The hair for my character’s head is made up of a blonde hair preset with some tweaks and then some spBlonde splines ,which I used to create some individual curls. The mental ray only started artifacing after quite a few curls were added , even though they don’t have that many hairs… Parts would render beautifully and then some seemingly random parts would render as almost solid blocks of colour.

#4

What brender time did you get with Maya Software and with MR? What biggest render time would be acceptable?

#5

Well the first character worked out to about 8min a frame in software and 30 minutes in mental ray . So I rendered the hair in software, the body in mental ray and comped the 2 together. With this new character it takes 1h40min in software and i did not even time the mental ray . If i do end up rendering in software i’ll split some of his furry elements that do not interact into separate layers. Actually the company i’m working for has promised to buy me a stronger pc , so hopefully rendertime is not such an issue…hopefully…

Thanks again!

#6

ps. obviously the faster the better. Even 8 min a frame for a 30 second piece of animation works out to a lengthy render. And then you only have your hair done and nothing else…Obviously 1h40min is out of the question . I have my fingers crossed for that new machine …

#7

Hello!
So I solved my problem by cheating and multiplying the hair render to get rid of the hole ;p
But now I’m experimenting with p_HairTK in the hopes that it’ll be kinder to me. But I’m stuck already…

Kiryha, I’m trying to follow a tutorial that i suspect might be yours : http://kiryha.blogspot.nl/2010/06/rendering-fur-with-mental-ray.html

I didn’t get very far I’m afraid… I completed the step that said : “Select shavedisplay node, assign p_HairTK. Turn off “override geo shsder” in material properties section of shaveHairShape.”
I changed the colour to bright blue, but when I render it it still turns out in the default colour. It’s a fresh file that I just created with a sphere and a standard shave preset (the redhead) . I did not change anything and shave globals are set to hair primitives. I closed and restarted maya. The file opens fine , but when I render it, the render comes out blank… Now I’m pretty sure I’m missing something really obvious, I just don’t know what…

Any wisdom anyone?

ps Thanks for all the help so far!

#8

Did you turn off “Override geo shader”?
Are you sure it still render shave shading(set in pHairTK noticeable colors, like puer ren for color and specular and render).
Actually, i use pHairTK soooooo long time ago and i can’t check your scene cos i can`t install pMegaTK, so may be i would not be much useful with problem solving in this area. Dont you want to try mentalcore?

#9

Yep, just double checked - i did all of that, picked a really obnoxious colour and still, nothing. Maybe I installed the plugin incorrectly…

I’ll try mentalcore next, the puppet shaders just seemed a little simpler to me.

Thanks for getting back to me!

ps great showreel by the way

#10

Well, you can be sure, mentalcore is life saver if you need to render in Maya and MR!
Workflow and shader assignment is very straight forward!
> great showreel by the way
Thanks! :slight_smile:

#11

Well, you can be sure, mentalcore is life saver if you need to render in Maya and MR!
Workflow and shader assignment is very straight forward!
> great showreel by the way
Thanks! :slight_smile: