# How to efficiently merge geometry and get rid of internal shapes, etc?

I have this object:

Think of what i'm doing as using prefab sections that are arranged to form shapes. I know how to snap and rotate. I'd like to be able to do a simple 2d Union of coplanar polygons, can anyone show me how. Is there an add-on perhaps?

• Please insert a new image with multiple perspectives. Quad view might be convenient. Is this a three legged table? Your image is cropped and flat illuminated so I do not have enough visual cues to understand what I am viewing. Do all vertices exist in a plane? – atomicbezierslinger Dec 29 '15 at 7:12
• @atomicbezierslinger Question edited with pictures. – Somatic Dec 29 '15 at 8:06
• I'm not sure I understand, do you want to merge polygons that are on the same plane, like this : i.stack.imgur.com/Fp2O0.png ? – zeffii Dec 29 '15 at 13:34
• @zeffii That is exactly what I want to do. – Somatic Dec 29 '15 at 17:09
• @Somatic feel free to edit or roll back my edit to your question if it doesn't reflect the core of your query. – zeffii Dec 29 '15 at 18:38

Primary

In case you want manual labor. Use a process that does not create unseen faces. Discard current model.

Use loop cut and extrude in the process.

Yellow Meshes Left to Right

Start with plane. Edit mode. [Loop cut] in X and Y. Delete face from Middle. More loop cuts and delete more faces as vertices. Select all and [Extrude] in Z-axis. One could claim extra loop cuts were made, thus extra geometry. Since I am not sure of your artistic goals I might claim the corners in your image have some roundness of bevels to them which would require more vertices.

Final Cyan Mesh.

Select a face on corner. [Extrude] X-axis. G Move excluding Z-axis.

Boolean Modifier

Here the cross mesh has two Boolean modifiers. You see intersect. My belief is it should read union. Yes troubling. I seek comments on that issue.

Boolean Modifier applied. Mesh copied to show in object mode and edit mode.

More Angles

In the image above the source face was selected to prepare a rotation origin. Cursor to Selection. Extrude on X-axis. Select only the extruded face.

Pivot point for rotation mode set to 3D Cursor.

Rotate 45 degrees on Z-axis. RZ45 Accept. Cursor to selection a second time for the extruded face. Rotate. RZ45 Accept. Perhaps you will need -45 in some cases due to my lack of bookkeeping. Angles are shown on the final product selected face. The two rotations produced the parallelogram. Set pivot mode to you standard to avoid confusion.

If you were to [create an orientation] this might help you. Not shown.

More Miscellaneous

Clearly the circles could be constructed by adding a Mesh Torus. The original design has a mirror symmetry at 45 degrees, X-axis, Z-axis, if we agree on axis names. So less work via that symmetry.

In the image above the wireframe is shown but in 3D View, but not in render.

• Is it possible to extrude at a precise angle? For example, on the cyan mesh, how could I make the extruded bit be exactly 45 degrees? – Somatic Dec 29 '15 at 22:06
• @Somatic. Yes see above edit. – atomicbezierslinger Dec 30 '15 at 7:09

You could try to merge vertices for a cleaner mesh by enabling the following options:

After that select a vertex RMB and move G displaced vertices over another vertex to merge them a circle appears around the target vertex confirm merge by LMB.

You could also add the reference image as a background image (only visible in orthographic mode).

Method 1 Use extrusion modeling. Extrude single edges E, rotate them R scale them S and if required move single vertices. This is what @atomicbezierslinger describes.

Method 2 Extrude one single vertex E along the contour of the reference image and add faces later F.

The easiest way would be to convert the bitmap into a .svg using e.g. Inkscape. and import the .svg to blender.

• This is useful, but it doesn't give me the control I wanted (the object I'm making has rotating bits and other geometry that's not in the image). Converting that path results in a bunch of unneeded vertices and edges, so it doesn't actually solve the problem. What I'm looking for is not a way to make this particular shape, but a method I can generalize to make any kind of intricate, precise geometry. – Somatic Dec 29 '15 at 8:36
• @Somatic I see, I added another alternative answer emphasizing my favorite tools, Alt-M is also useful to merge vertices. – stacker Dec 29 '15 at 9:17