SimplyMaya Forums

Welcome to the forum, feel free to ask questions here.

Home / forum / Lounges / Maya Basics & Newbie Lounge / What is wrong with this Porsche?
Register FAQ Members List Calendar Mark Forums Read

New Thread
 
Thread Tools
Old 04-05-2010, 01:28 PM   #1
nectario
Registered User
 
nectario's Avatar
 
Join Date: May 2010
Posts: 16
Thanks: 0
Thanked 0 Times in 0 Posts
Default What is wrong with this Porsche?

Hi,

I have a black Porsche model, which I am trying to render it using mental ray in Maya 2011. I'm placing it with Sun and Sky created in mental ray. I selected the all the maximum quality settings: Production Quality, Global Illumination, Final Gather, Refractions, etc. etc.. When I render it, the car comes out grayish/blueish. Below is an example:

http://www.nektarios.com/Black_Porsche.jpeg

Even though the car is black, why does it look grayish/blueish? I tried everything to make it look black, but to no avail. Keep in mind this only happens with the Sun and Sky setting turned on in Mental ray. Your helps is appreciated! Btw, the material on the paint is Phong.

Thank you!

-Nektarios
Attached Thumbnails
Click image for larger version

Name:	black_porsche.jpg
Views:	76
Size:	180.0 KB
ID:	44157  
nectario is offline   Reply With Quote
Old 04-05-2010, 02:17 PM   #2
jsprogg
Lifetime Member
 
jsprogg's Avatar
 
Join Date: Feb 2004
Location: Chicago
Posts: 1,708
Thanks: 0
Thanked 85 Times in 77 Posts
Default

thats exactly how its meant to look...when you use Physical sun and sky you will get the ambient bleed of the sky which of course is blue , to make it less noticable change the time of the day so the sun is lower in the sky to either morning or evening and possibly change it to a winter month too . If you want it black then you need to do a studio render .
__________________


2 x Modeling Challenge Winner

Last edited by jsprogg : 04-05-2010 at 02:19 PM.
jsprogg is offline   Reply With Quote
Old 04-05-2010, 02:28 PM   #3
nectario
Registered User
 
nectario's Avatar
 
Join Date: May 2010
Posts: 16
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Thanks. So how can I get the shadows in the Porsche appear blacker then? I still need it at an outdoor setting.

Cheers,

-N.
nectario is offline   Reply With Quote
Old 04-05-2010, 02:44 PM   #4
leonlabyk
Registered User
 
Join Date: May 2006
Location: Hastings UK
Posts: 892
Thanks: 3
Thanked 32 Times in 31 Posts
Default

You could lower the gamma. If you open up the hypershade and goto the utilities tab you should find a node called mia_exposure_simple. If you click on this it will open up the settings where you can try lowering the gamma to make the render darker.
leonlabyk is offline   Reply With Quote
Old 04-05-2010, 02:49 PM   #5
nectario
Registered User
 
nectario's Avatar
 
Join Date: May 2010
Posts: 16
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Thank you! :-)
nectario is offline   Reply With Quote
Old 04-05-2010, 03:35 PM   #6
Gen
Moderator
 
Gen's Avatar
 
Join Date: Dec 2006
Location: South FL
Posts: 3,499
Thanks: 16
Thanked 645 Times in 567 Posts
Default

I really wish that the physical sky was implemented properly because everyday someone will run into this problem. When the physical sky is created, it attaches a lens shader to the camera to control the exposure(else you'll see exactly how bright the sun is) and that lens shader also has a gamma property and that is set to 2.2 which is the default gamma on monitors (the physical sky setup assumes you are working in a space where the gamma is 1.0 also known as linear space).

The thing is, when you choose colors from the color picker or use or your jpeg and other 8 bit textures they already have a gamma of 2.2 embedded (or else they won't look normal and pretty to human eyes), so now, you have your colors and textures being hit twice by a gamma of 2.2 which causes the washed out look. You can fix this by countering the embedded gamma, plug in gamma utilities(as you would with any other texture) into your shader(excluding bump, normal and displacement maps) then you can use the gamma node's value to plug the textures or change the color. The gamma node's "gamma" should be set to the inverse of 2.2 which is .45454545454 or you can round that to .455

Apart from that, I think part of your problem is the fact that your car is highly and equally reflective regardless of viewing angle so it's showing a lot of everything else but it's diffuse color and car paint doesn't do that. If you were to browse the mental ray materials section of the hypershade you should see carpaint shaders.
__________________
- Genny
__________________
::|| My CG Blog ||::
::|| My Maya FAQ ||::
Gen is offline   Reply With Quote
Old 04-05-2010, 03:53 PM   #7
nectario
Registered User
 
nectario's Avatar
 
Join Date: May 2010
Posts: 16
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Wow! Thank you!!! VERY insightful! I will do that and see what the outcome looks like... :-)
nectario is offline   Reply With Quote
Old 05-05-2010, 12:32 AM   #8
nectario
Registered User
 
nectario's Avatar
 
Join Date: May 2010
Posts: 16
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I re-rendered with all suggestions. Much better! :-) See image below!
Attached Thumbnails
Click image for larger version

Name:	porsche 03-small.jpg
Views:	53
Size:	96.0 KB
ID:	44159  
nectario is offline   Reply With Quote
Old 05-05-2010, 02:45 AM   #9
Gen
Moderator
 
Gen's Avatar
 
Join Date: Dec 2006
Location: South FL
Posts: 3,499
Thanks: 16
Thanked 645 Times in 567 Posts
Default

Huge improvement, good job!:nod:
__________________
- Genny
__________________
::|| My CG Blog ||::
::|| My Maya FAQ ||::
Gen is offline   Reply With Quote
New Thread

« Previous Thread | Next Thread »

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off

1 Month

$34

Month-to-month billing
$34/month
Unlimited access to all videos
Project files to download
Easy to cancel at anytime
 
 

3 months

$87

Billing every 3 months
$29/month
Unlimited access to all videos
Project files to download
Easy to cancel at anytime
Save $5 per month or $15 in total compared to monthly billing with this package.

12 months

$288

Billing every 12 months
$24/month
Unlimited access to all videos
Project files to download
Easy to cancel at anytime
Save $10 per month or $120 in total compared to monthly billing with this package.

Your plan will automatically renew. You can cancel at any time via your PayPal account to avoid being charged again.

You can view the FAQ on our video plans here. You can contact us directly here. By clicking one of the buttons above, you agree to our Terms and Privacy Policy.