CGTalk - SHAKE- shadows image as Alpha Maps.

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Glenfx

12-31-2003, 11:21 PM

I created a black and white image of the shadows in Maya but it doesnt have an alpha map, the idea is to convert that image into an alpha map in SHAKE.
(Im Using Shake 2.5 for the PC)

So, i composited the scene with all the objects and the background, but i have trouble with the shadows.

For the shadows i added a node of "SetAlpha" to the B&W shadow image and the alpha propertie i gave it a number of 0, so i got rid of the black area. But i cannot change the white area to black since it simply dissapears.

I also tryed creating a black color image and linked the B&W Shadow image to the side of the color node as its supposed to be for the masks. But didnt work.

I also tryed creating a layer, in the right side i placed the color image and in the left side i placed the B&W shadow image with a "SetAlpha" node. and still didnt work.

So my question is... How do i make the B&W Shadow image to be an alpha map of a dark color image to make the shadows in Shake?

Or how do i make the shadows with the B&W Shadows image inside Shake?.

I know i can use photoshop to make the alpha map.... but this is going to be used for an actual secuence, so its quite annoying to create alpha maps to hundreds of images.

Thanks and HAPPY NEW YEAR
GFX

FKMaster

01-01-2004, 02:49 AM

Originally posted by Glenfx

So my question is... How do i make the B&W Shadow image to be an alpha map of a dark color image to make the shadows in Shake?

GFX

add to your shadow map a "Reorder"-node from the clor-section....set channel to "rgbr" now you have an B/W alpha-channel for the picture....now copy the alpha to your other picture with a "copy"-node from Layer-section.....

like this......
http://www.fkmaster.de/tests/shadow.JPG

Glenfx

01-01-2004, 03:59 AM

Hi, FKMaster, i did what you told me, but it didnt work. Im attaching a screenshot of the problem and how its composed.

I reversed the link order of the copy node, if i made it like your screenshot then i woudnt see anything.

Im also wondering if an "image color node" from shake isnt advisable... ill try importing a black image to test this.

Oh, what i need is the shadows to be black and not white as you see in the image i attached here.

http://glenrifx.iespana.es/glenrifx/help.jpg

Kvaalen

01-01-2004, 08:43 AM

I don't use shake, but shouldn't inversing the color do it?

FKMaster

01-01-2004, 01:48 PM

the shadow image must be the right input-connection of copy-node.....

other way to add shadow to an image:
add to your image a layer-node and change the operation to ISub....
the right input of the node must be the shadow image....
shadow image:
the shadow must be white or grey and ohter parts of the picture must be black.....
like this
http://www.fkmaster.de/tests/shadow2.JPG

Glenfx

01-02-2004, 01:15 PM

Kvaalen: actually, no, because i would still have white areas.

FKMaster: Thank you, the "ISub" node worked great :)

I have another question...
as you can see i have a couple of ice cubes, and im testing by rendering in parts, so i have my ice cubes rendered alone, but since im not rendering the background i lost the refraction effect on the ice cubes, so when i composite them i only see them transparent. i was wondering if i could use a copy of the ice cubes animation and make it a displacement node behind the untouched animation of the ice cubes to regain some of the effect.

If i can do that.. how can i do it?

Thanks

arvid

01-02-2004, 07:05 PM

Try IDisplace, but you'll need something to drive the deform with, perhaps an incidence pass from 3D

FKMaster

01-02-2004, 11:46 PM

yes the IDisplace-node ist not bad.....:thumbsup:
add iDisplace to your background and for right input use the
ice-cubes-image and switch ychannel xchannel of IDisplace node to blue.....
-->play around with the sliders....:)

Glenfx

01-03-2004, 02:51 AM

Yep, IDisplace worked great :D

Thanks FKMaster and Opacity for the help. :bowdown: :thumbsup:

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