vray lights and alpha channels

[mikeh]

correct me if i'm wrong but it would seem that vray lights do not work with single planes that are mapped with materials that have alpha channels...for example, a 2d tree mapped to a plane facing the camera. is this correct, it is what i am getting in playing with vray lights (which are completely new to me)....or am i not setting something correctly...the materials are Forests "Planes" materials.
mh

[Morbid Angel]

vray mats do not support bitmaps. only dome light and only for specific purpose.

[mikeh]

vray mats do not support bitmaps. only dome light and only for specific purpose.

I'm lost with this response. "Vray mats" is an abbreviation for vray materials?...I guess i don't understand the response in regards to shadow casting from a vray light on a plane with an alpha channel. sorry.
mh

[Morbid Angel]

sorry my mistake, i ment vray lights.

[meanadam]

Mikeh is talking about the opacity problem.

It does work:
http://www.chaosgroup.com/forum/phpB...ic.php?t=13213

[mikeh]

Mikeh is talking about the opacity problem.

It does work:
http://www.chaosgroup.com/forum/phpB...ic.php?t=13213

Ok...I guess I am not being clear enough...Yes I can get alpha channels to work with vray...but...not using a vray light. I have to use advanced ray trace light.

So, I will repeat..."Vray lights" (not lights used in vray) do not cast shadows with planes with alpha channels...as far as i am able to tell...at least i can't get them to cast shadows....I have to use a non-vray light when using the Vray renderer in Max.

The link i was sent to has no mention of "vray lights" working with Forest. I use the paid-for version, Forest Pro.

Thanks, if you can show me how to get vray lights to work with alpha channels. I had hoped that i could speed up render times by using vray lights but at this point that doen't appear do-able.
mh

[meanadam]

Use the Vray Shadow on your Direct, spot, whatever light. Make sure "transparent shadows" is checked.

Your vray light plane is probably too large and casting a soft shadow.

[mikeh]

Your vray light plane is probably too large and casting a soft shadow.

That was the problem, light too large...thanks for the insight.
mh

[mikeh]

well, now that i was able to use a vray light and compare it to a direct light using advanced ray trace for the same scene it would seem that vray lights are NOT the way to go. The scene took one minute longer to render using the vray light and had strange artifact lines thru parts of it...a double whammy. The images are part of an animation. Vray light took 3 minutes per image while the direct adv ray trace took 2 minutes per image and had no artifacts. I would post the comparison images but, being new to the forum, i don't know how.

I'm used to getting animations down to one minute per frame so this is all exploration to get something similar using vray and GI. I don't expect to match the speed of scanline rendering but i guess that is the price one pays for GI....but i have managed, with a bit of trial and error to shave 3 minutes off my vray initial times. These are all 720x480 dvd sizes. The big camera match stuff, larger images are another story.

mh

[Candelero]

@ mikeh
About posting images, take a look at this thread:
http://www.chaosgroup.com/forum/phpB...ic.php?t=12769

Best regards,
nikki Candelero