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Pasting sections of image onto object

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Asa Desouza-Jones
Pasting sections of image onto object
on Dec 7, 2019 at 3:35:47 pm

Hi there,

I need some advice:

I've made a model of a building under construction and want to add an image to the tarpaulins I've put around the window areas. I have a couple of issues I need some help with.

First: when I highlight a section of the tarp with the live selection tool then paste an image in it, it removes the original material I had for the overall tarp - is there a way to rejig the order of the materials to have them both on the same object?

Second: when I paste the image onto the tarp it's displayed quite crudely on the surface, is there a way to blend it onto the surface so that there isn't the lines showing around the edges.



Thanks


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Steve Bentley
Re: Pasting sections of image onto object
on Dec 11, 2019 at 5:21:25 pm

Second question first: If you are using a selection or selection set to map the second material on top of the first, the "blend" at the edges will only be as fine as your mesh. There is a spot at the edges of the selection where the texture will be there for one "row" of polys and then not there the next. So it can be a pretty hard cut off where the texture ends. You can either use a soft edge alpha to map the overlapping texture on top of the underneath texture or you can use Body Paint to paint the image on to a UV map and feather it that way.

As for mapping; if you can get a straight on view of the area you want to map to, you can drag the second texture to the object in the object manager, then "set selection" for the polys you have manually selected and name that selection. Then put that name in the second material tag's attributes under "selection". That will restrict that second material to that set of polys. (alternatively you can drag the material to that selected set of polys and cinema will do all the naming and restricting for you). Then right click on the material tag and choose "fit to region" and draw a bounding box around those selected polys (this is why you need a good straight on view as you can only drag a rectangle). That will size the second material to those polys. You can now tweak that sizing with the mapping attributes in the material attributes.
To my knowledge there is no "Fit to selection" which I've never understood - I think that would be super useful.

You can also just do a flat mapping and manually position, rotate and size the texture to the entire object (no selection sets) and then the edge of the second material is perfect (or as perfect as its alpha will allow)

I wasn't sure how one copy and pasted a texture to an object so I was not able to see the results you were seeing with the replacing texture.



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Asa Desouza-Jones
Re: Pasting sections of image onto object
on Dec 17, 2019 at 7:50:28 pm

Thanks Steve, I've got the mapping of the materials sorted now and it's starting to look a lot better.
Just wondering how to resolve the hard edges of the second material, do you know how I use the soft edge alpha, I've had a little look around on the materials section but can't find anything.

Thanks again for your help.


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Steve Bentley
Re: Pasting sections of image onto object
on Dec 17, 2019 at 8:32:19 pm

Ya that's pretty easy. You can have a soft edged (or blurred) alpha in the alpha channel of a PSD or you can just use an image of your choosing. It needs to be soft in the actual image so you will need to do that in pshop (the alpha should be soft not the image). The image part should extend past the blurry edge.
This psd with an alpha or just a gray scale image that is going to be the alpha needs to be put in the "alpha" channel of the material. If the alpha is part of a pshop file you can go with the default settings, (in this case the same psd would be in the color channel and the alpha channel of the material and c4d sorts out what part of the image it needs) but if the image you want as the alpha is just a separate image you sometimes need to uncheck "image alpha" in the alpha settings so that C4D doesn't think its a psd and go looking for an embedded alpha.
Make sure to double click the material in the material manager so that it brings up the material editor. Not all the settings show well if you just the use attributes dialogue that comes up when you single click on the material in the material manager.
That "soft" button is more for aliasing issues rather than making a hard edged alpha blurry. You will need to make the alpha blurry in an imaged editing package like Pshop.
Make sure to put the material with the alpha to the right in the list of tags and materials on the actual object in the object manager: things to the right overlap things to the left. You are basically shining the second material through the window that is the alpha, on top of any materials to the left - white is clear and black is opaque in the alpha "window".
And don't use the " mix textures button" in the tag's attributes. That works for things that can't really be alpha'd and will mix, say, a bump from one material with the bump of another.







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Asa Desouza-Jones
Re: Pasting sections of image onto object
on Mar 5, 2020 at 11:27:08 am

Amazing that's worked, thanks for your help!


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