Adding UV Mapping to Mesh

Question

I am trying to apply an image to a wavy mesh I created in Blender. I am not sure how to do this. I don't think I have any seams because its one panel so I tried just unwrapping which didn't work. Then I tried marking the edges as seams but this also failed to work. Where are the seams if any and how do I apply an image?

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I'm afraid your link doesn't work here, can you add a screenshot? stackexchange allows adding pictures inside the posts. — Antony Riakiotakis, Jun 13 '13 at 15:43
Yes. I have an image to span the entire side of the container — BDGapps, Jun 13 '13 at 16:03

score 12 · Accepted Answer · edited Jul 17 '16 at 00:54

12

Blender has a difficult texture mapping system.

To view an image on a 3D model, you need to do the following:

Select a mesh object and go to Edit Mode.
If the mesh has not been unwrapped, define your seams (Ctrl + E > Mark Seams) and unwrap it (U). Only the selected faces will be unwrapped, so make sure you have what you want unwrapped selected. Also, only the Unwrap choice guarantees that faces will have the same more or less spacial layout in UV space as they have in the 3D mesh surface, seams included.
Switch to a UV Image Editor while still in Edit Mode.
If your mesh has been unwrapped and there are some faces selected in the 3D Viewport, these faces' uvs should appear in the UV Image Editor. If this does not happen, make sure there is no render result displayed on the UV Image Editor.
Now you can assign an image to your mesh by either opening a new one from the menu Image > Open, selecting an already opened image from the drop down menu or generating a new image from the menu Image > New.
This image will be applied to the selected faces. However, it may not appear in the 3D Viewport yet. For that to happen you have to set your 3D Viewport to Textured View by hovering the mouse inside it and pressing Alt + Z. You can also change it the view manually in the footer.
If you try to render your mesh, there will be no image on it. The image has simply been attached to the mesh's UV layer. To make the mesh render with this image, you need to explicitly create a material, add a texture and change the texture's type to Image, set the image, change the Mapping to UV and assign the texture to color.

Yes, it is long winded and confusing. Sorry :)

edited Jul 17 '16 at 00:54

Shady Puck

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answered Jun 13 '13 at 16:09

Antony Riakiotakis

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I understand how to do everything except "If the mesh has not been unwrapped, define your seams and unwrap it (shortcut U)" Can u please look at the image and explain where the the seams are because I am confused as to where they are. Thanks. – BDGapps Jun 13 '13 at 16:13
@BDGapps you don't need seams, it is a flat object. And if you did have any, they would be around the edges. – iKlsR Jun 13 '13 at 16:17
Seams usually show up as red so you may not have defined them (It's not very clear from the image), to define them use Ctrl-E->Mark Seam when in edge select mode. But even selecting the faces you want to unwrap and unwrapping them is sufficient. However I don't think the issue is with that. For instance, you haven't applied an image in the UV editor in the right screenshot. – Antony Riakiotakis Jun 13 '13 at 16:20
If u look at my image on the right side you will see what shows up when I don't mark the seams. It does not look like the same mesh that has been unwrapped. – BDGapps Jun 13 '13 at 16:25
As explained in 4, only selected faces show up in the image editor. So if you select all with A you should see everything. I worry though that the rest of the mesh may not have been unwrapped. Did you select all before unwrapping? (I suspect not, if you haven't defined any seams) – Antony Riakiotakis Jun 13 '13 at 16:28
If u look at it when I put an image over it the mesh doesn't unwrap correctly. – BDGapps Jun 13 '13 at 16:29
@BDGapps try going into top view and choosing Project from view when unwrapping. I don't know why you are getting so many pieces. Additionally, make sure you have no stray seams about. Use Ctrl + E to clear them – iKlsR Jun 13 '13 at 16:30
To get continuous faces of the mesh stay continuous in UV space you need to use the first Unwrap option, not smart unwrap or lightmap packing. – Antony Riakiotakis Jun 13 '13 at 16:31
@Psy-Fi I am just using the regular unwrap – BDGapps Jun 13 '13 at 16:34
@iKlsR can u please explain what you mean by this "choosing Project" from view when unwrapping – BDGapps Jun 13 '13 at 16:35
@BDGapps go into the view where the large side of the object is visible and press U to unwrap, but choose Project from view, this should make a flat uv map. – iKlsR Jun 13 '13 at 16:38
Then you must have defined seams everywhere. Delete them by selecting everything and using Ctrl-E->clear seams. Define them properly, only at the sides of the Container. Note after redefining seams, you have to reunwrap. – Antony Riakiotakis Jun 13 '13 at 16:38
@Psy-Fi am i doing mark seam or mark seams – BDGapps Jun 13 '13 at 16:43
Oh, it's singular, sorry :) – Antony Riakiotakis Jun 13 '13 at 16:45
@iKlsR I have no "Project" in view. Next to where I select that I want to view to be UVImageEditor the next button says view but when I click on it Project is not there. – BDGapps Jun 13 '13 at 16:45
@BDGapps Project is an option when you press U for unwrapping – Antony Riakiotakis Jun 13 '13 at 16:45
@iKlsR that got it to work but the graphic is on both sides of the container and I only wanted it on the outside – BDGapps Jun 13 '13 at 17:20
@AntonyRiakiotakis by any chance can you please update python script for the same – gonephishing Apr 01 '18 at 12:57

score 4 · Answer 2 · edited Jun 10 '20 at 12:57

You definitely don't need seams for this mesh. Seams are to unwrap something that is not flat like a ball or character.

I recommend the following:

In edit mode select all vertices A
Ctrl + E, choose Clear Seams
Deselect all with A, then select only one wall of your model. C is a good tool for this.
press the numpad 1 or 3 so that the viewport is looking directly at that wall. It's best not to be in perspective mode, change to Ortho by pressing 5.
Press U and choose Project from View
Because you only have one wall selected, in the Image Editor there will only be one wall . Use G to grab, R to rotate your unwrapped mesh in the Image Editor. Preview in the 3D Viewport to line up your texture as you like.
Repeat steps #3. through #6. for each wall. Note that its ok if your walls over lap in the Image Editor when all selected. Also, a good tip is, if Numpad 1 gives you the view of the front wall Ctrl + Numpad 1 will give you the back.
If you haven't already, follow Psy-Fi's #7 step to add you texture to the mesh as a material texture. Now you can render.

A couple things you need to understand about this texturing process is:

Un-wrapping your object and opening an image in the Image Editor has not textured your object even if the texture shows up in the Viewport. Only when you actually assign a material with the desire texture is it textured. The reason is, Blender's Image Editor is a really powerful tool that allows you to paint a image texture by drawing directly onto your mesh object in Texture Paint Mode. So, it allows you to view images on a mesh even when they are not its assigned texture.

i updated your post with the kbd syntax, have a look at the source. — zeffii, Jun 13 '13 at 18:24
Project from view is indeed how an image would have been mapped onto this container in reality. Seams are used by the Unwrap tool which will flatten and stretch out the side as if it was e.g. a piece of cloth. If an image is mapped like that it will be distorted too much. — brecht, Jun 13 '13 at 19:09