[Eric Lagman]

I guess this is more of a photoshop question. Does anyone know a way to clip images from the backround using the magic wand and alpha/object channel image that maxwell produces and get a clean edge. I always struggle with the edges being all jagged compared to using the path tool. With the path tool I always get a clean result, but it takes hours on a complex model to cut it out. There has to be a quicker and clean way using photoshop and the channels provided by maxwell I just don't know what they are. Any ideas?

[RonB]

Hi Eric,

There are various methods, it depends on what kind of background you are using. Easier if you are using a solid background...depending on the general color of the model use either a blue (0,0,255) screen or green (0,255,0). The selection can then be created from Channels and will be very clean. But if you are trying to lift a section of a scene and you are using the Magic Wand, after the selection is made expand it by one pixel and turn on Quickmask, apply a Guassian blur to the mask at one pixel, turn off Quickmask and use it.

You might also buy a commercial mask tool if you do this a lot, there are quit a few to choose from, just Google it.

Hope that helps some.

Cheers, Ron

[Bubbaloo]

Render an alpha channel with your render, then in ps open the main render and add a mask to the layer. Open the alpha render and select all and copy clip it to clipboard. In your layer with the mask channel, alt-click on the mask and the screen will turn blank. Paste the alpha in there and you will have a clean clipped background!

[Eric Lagman]

Thanks guys. Bubbaloo the technique you described worked perfect. Thanks for the step by step how to.

[Bubbaloo]

I have to help someone every once in a while to offset my pointless rambling posts...

[leoA4D]

Eric, after the mask, you may find a black line or edge at the perimeter of a light object against a light background. If you do, Mihai recommended: "For the black edge, you can run the command Remove Black Matte in PS (Layers>Matte>)." (http://www.maxwellrender.com/forum/view ... hp?t=24239)

I had the edge and it was a pain.

[b-kandor]

There was a great thread/tutorial on this just recently somewhere on the forum???

[Bubbaloo]

There was a great thread/tutorial on this just recently somewhere on the forum???

Yeah, that's where I learned to do it...

[Joedex]

Hi Eric, this web site used to have a very good photoshop tutorial on just this subject.... http://www.russellbrown.com/tips_tech.html

[martgreg]

does the alpha chanel render at the same time as your regular rendering, and how does maxwell know which objects to make white and which to make black....

I have a product and I have the background.. I obviously want to get rid of the back ground after the render has cooked.

is there an option to select objects to make black and white ..

I know there is a render check box and a alpha check box but I haven't had any luck ..

please help me

[Bubbaloo]

does the alpha chanel render at the same time as your regular rendering, and how does maxwell know which objects to make white and which to make black....

I have a product and I have the background.. I obviously want to get rid of the back ground after the render has cooked.

is there an option to select objects to make black and white ..

I know there is a render check box and a alpha check box but I haven't had any luck ..

please help me

To get your alpha render, you have to specify an image output path.

[Eric Lagman]

does the alpha chanel render at the same time as your regular rendering, and how does maxwell know which objects to make white and which to make black....

I have a product and I have the background.. I obviously want to get rid of the back ground after the render has cooked.

is there an option to select objects to make black and white ..

I know there is a render check box and a alpha check box but I haven't had any luck ..

please help me

What I end up doing is doing a render without alpha then having to go back and hide the background and render it with only alpha checked. I wish there was an exclude from alpha check box for objects so that this could all be done in one rendering step.

[Bubbaloo]

What do you mean by hide the background? Geometry will show white and background (empty space) will show black. Transparent objects can also be black.

[martgreg]

My co worker said that was probably the way to do it .. damn he was right.... so we have to render the render twice.. i guess it doesn't have to cook for long as the scene is way more simple.. do you have any ball park percentages on how long it takes to run a alpha render compared to a regular one..

thanks for the quick response

[martgreg]

What do you mean by hide the background? Geometry will show white and background (empty space) will show black. Transparent objects can also be black.

Here is an screen cap of my image the product is blurred out... but as you can see the seamless background is also geometry and therefore is there a way of getting a aplha chanel in one shot , as opposed to doing what Eric mentioned ?

thanks for your help