How to create tree alpha images in Carrara

[ivke]

I am using Carrara5Pro and I want to know how you can create tree alpha and or tree alpha negative images using Carrara only. So it is easier and faster done, and I do not need to learn an other package. I have attached some tumbnails from the Little Planet tutorial I have.

[Piem]

Hi
It's really easy.
Open Carrara
Make a plan (from the primitive)
Rotate the plan toward the camera (if needed)

Select the plane and clic on the shader room

- Put the tree image on the color channel as Texture Map
- Put the Negative in the alpha channel as Texture Map



Notice that the more precise is your image, the best result you'll have
You can, in the Render room, activate the "light trough transparency" and put a spotlight behind the plane and even add to the spot a cone effect (3d) to see more interresting results.

[rickei]

yep, do what Piem said

this technique works really well for groups of trees.

another tip: you can duplicate the first plane and rotate it 90º for a tree that can be viewed at different angles. though this can be a little more difficult to light.

I do this a lot with architectural renderings. You can add people to the scene in the same way...a photo and an alpha map.

[smudgee]

hmm..i read this question differnt, i thought the original poster wants to use carrara's 3d trees to make a 2d image of a tree with alpha channel- so he can pop that into photoshop/game engine/whatever.

If so, just insert atree into cararra scene, line up camera, adda light or two.
Set backdrop to black, then in "output tab" in render room choose format that supports alpha channel.(psd/tiff/targa ?). Enable check box "render alpha channel"

Thats it bascially.
smudgee

[ivke]

Thanks guys for the info, I should have clarified my thoughts a bit better.

What I basicly wanted was to use one of the Carrara trees, render that, what is thumbnail 1. Change than the render settings over and use the same tree or the image to produce thumbnail 2 & 3, because I do not have the last two. So I can apply them as a bump map!

[rickei]

OK I think i know what you are saying. though the "bump map" thing really has me confused...again

you do not need image 2 or 3.

create and light a tree. set your camera to the POV you need but be sure the base of the tree is at the bottom of the render.
in your render settings check "render alpha channel" and "Use premultiplied alpha" and set your file format to Photoshop 2.5
render and save.
now you can create a plane an apply your rendered image
then, select Texture map in the alpha channel and import the rendered image. than click premulitplied alpha and select alpha only. that will only use the embedded alpha channel in the original rendered image.

[rickei]

it's actually 1 step easier. just import the rendered image into the color channel and check the color and alpha channel option.

the first image shows your render setting to produce the alpha channel.
the second image shows a plane with the rendered image of the tree applied to it

[ivke]

The reason for image 2 and 3 that when I apply them all to the same plane I will get a more realistic image, I want to place the tree alpha image in the bump channel. The flat planes in the far background of the scene are quiker rendered then a whole bunch of 3D trees when I do not need the detail there.

[bwtr]

Placing a tree image on a Billboard and replicating that can make very lightweight background tree effects also.

[rickei]

Originally Posted by ivke

The flat planes in the far background of the scene are quiker rendered then a whole bunch of 3D trees when I do not need the detail there.

this is what I am trying to show you how to do

if you will read my previous posts it shows you exactly how to prepare a tree to be put on a plane(billboard)...and there is no need for your image 2 or 3

Originally Posted by ivke

The reason for image 2 and 3 that when I apply them all to the same plane I will get a more realistic image, I want to place the tree alpha image in the bump channel.

if you add the alpha image to the "BUMP" channel you will get absolutely no effect. an alpha image has no bump information...only alpha information. I think maybe you are using the wrong terminology.