I'm trying to merge down the picture layer on the sides of the cube, however, the results is that the image is merged down on the sides that I don't really intended. I'd like the picture to wrap the front sides of a cube that are actually visible.

How should I solve this?

Here are the pictures:


enter image description here


enter image description here

  • What do you mean with merge? Do you want to add that circle as a texture on the cube? Why not use the 3D tool for that? What's the end result you want?
    – Luciano
    Apr 11, 2018 at 11:26
  • Thanks for your response. My goal is make an optical illusion out of a cube so that the viewer would be able to see a circle from the specific viewing point (1st image). This means I need to overlay/merge the existing circle layer on top of the cube. Here's another image of the result: ibb.co/kKBPjx. Please note the differences in spaces between the horizontal lines on the top side of the cube vs the left and right side of the cube - this actually helps create the illusion. However, some parts of the circle are missing, for some reason they are on the bottom of the cube. Apr 11, 2018 at 19:04

2 Answers 2


I think this can help you.

Select and unwrap the front.

Select the Front Merged Material Layer and Edit its texture.

Now you will see the results in the cube while you paint the the texture.

See images below.

enter image description here

  • Thanks for your reply, please look at my comment on top. Apr 11, 2018 at 19:12
  • Apparently, in my case I needed to select Generate UVs and then Merge Down the circle layer with the cube. Thanks! Apr 11, 2018 at 19:40

Obviously you want 2D images of the visible cube sides for making a real cube.

The projections of the circle on the sides of the cube are elliptical arcs. A competent person could calculate their radiuses and main axles. Making the projection with a 3D program is much easier than performing those calculations manually.

Even in simple freeware 3D programs you can project your circle + other details onto a cube from the wanted direction. See an example. At first the circular shape is constructed on a plane.

enter image description here

Unwanted parts are trimmed away and the plane is rotated to the wanted position relative to the cube. The pattern is projected onto the surface of the cube.

enter image description here

This can be enough for your purposes, if you do not need more 3D operations. Simply save the cube surfaces as 3D vector drawings.

I tried to etch the pattern into the cube. Here's 2 different projections of the result:

enter image description here

enter image description here

ADD: Because straight lines are straight lines also in the projection, you do not have to draw all of them in a 3D program. Most of them can be inserted manually in a drawing program if you have 2D images of the projection of a circle and its diameters from 9 to 3 and 12 to 6 a'clock.

Here it is done and opened in illustrator:

enter image description here

The cube is seen in isometric projection and the center of the circle is aimed to the nearest corner of the cube.

  • The theory is right, the question is though how do you actually project the circle in practice? Since I'll have to print and build the actual cube with the corresponding optical illusion the flat vector image that you posted on the right is of special interest to me. Apr 12, 2018 at 16:13
  • @user1860809 I can show how the flat Illustrator image was generated from scratch, if that's what you wanted. The work is elementary. You must draw all small details of the projected circular shape by yourself. It's surely easiest before the projection. Get that freeware 3D CAD program. It's DesignSpark Mechanical (=a heavily decimated version of SpaceClaim, but still useful). It has line drawing generation disabled, but you can print a PDF like I did. That's editable in Ai.
    – user82991
    Apr 13, 2018 at 6:48

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