mental ray soft shadows

[Ras]

Hi guys

 

I´m trying to find out how to make shadows that gradually turn from sharp to soft as it runs along a wall.

 

I´ve tried using mental ray shadow map but that just makes uniformly soft shadows. Using raytraced shadows produces sharp shadows.

 

In theory a shadowedge should get more and more soft the further away from the edge that cast the shadow it is. - shadow from a building in sunlight would be softer edged than a shadow from a teaspoon on a table, right?!?

 

Anyway, Ivé tried to illustrate what I mean in the attached illustrations.

[joske]

no big deal : thats what MR lights are for :

 

use Mr area spot with raytrace shadows

then change the area light parameters width and heigth untill effect is as desired

if you have to much noise in the soft areas then up the sampling from 5 to 10 15 20.... until good, this will give longer rendertimes however

[Ras]

Thanks Philip

 

I am already using an Area light for this scene (it is turned of in the attached picture to show the issue more clearly). I am familiar with the qualities of arealights but since there is no mr Direct Light (ie no parallel rays) I was wondering if there would be any way to set a standard direct light to do this if I was using radiosity for example?!?

[joske]

you will not get the result you described with a direct light

only with an area spotlight

 

have a look at my example (thats a 'POUF' from Quinze and Milan by the way ) i made last night... sharp shadow on the start -> further away the shadow gets more blurry

 

you will get a bigger effect when using higher and longer objects (like windows)

if you pull back the spotlight far enough you will get almost a 'direct' light, and your blurring will decrease accordingly, but never dissapear.

 

if you would use a direct light : you will have no 'area shadow' because it does not have a distance and surface to average the shadow from (not sure, but it seems logical to me )

[Ras]

Hi Philip

 

Yeah - it is of course logical that an infinitly small point casting parallel rays wouldn´t have the desired effect - but then again - you have the mental ray shadow map that will make softer edged which isn´t logical either is it?!

 

I was simply asking if there was any way to tweak a parallel light to do as described. I gues not.

 

Thanks for your advice. I will resolve to using mr area spot placed far away to give as parallel rays as possible.

[joske]

well you will not need to place it very far, it will be almost impossible to tell the diff even if it is on a normal distance.

So don't hesitate to use the spotlight, you will know, but nobody will see the difference

 

check out my signature dude : that's there for a reason you know

[bob007]

Hi Guys,

 

I am new in this community. I am a student and pursing animation and visual fx. My most keen part is modelling, texturing and lighting.

 

Yes I do agree that Mr area spotlight is really good to achieve soft or blurred shadows and also for opacity maps but it takes long rendered time which is quiet not acceptable. To avoid such long render time I have used mental ray shadow map in one of my scene created in 3ds Max( scene is basically portrayed for rainy season). But I am having some problem with mental ray shadow map.

 

Since few opacity maps also has been used within the scene, under mental ray shadow map parameter till transparency remains off, all shadows seems blurred as desired but once I turn on or enable transparent shadows then all shadows started to displace from its positions which is not understood to me and it creates mess in my scene. For better understanding I am attaching both rendered options of my scenes (i.e- mental ray shadow map without transparent shadows and mental ray shadow map with transparent shadows).

 

Any advice or any solution would be highly appreciated.

 

Thanks in advance!!