How to render an object as a transparent wireframe?

Question

I'm a psychology student (and 3D design noob) who's been tasked with designing items for a test of spatial ability like this example...

I've been playing around with Blender, and I've gotten this far...

So the shapes I want are there, but I'm having trouble getting out rendered on white with black outlines.

I tried changing the World Horizon Color to white, which fixes the background, but the cube object renders solid. Any ideas on how to get it outlined like in the example?

P.S. That "LS" in the example is meant to be a window. Any suggestions on how to accomplish that would also be wonderful; I haven't even attempted it yet.

Answer 1

One way you could do this is by using freestyle:

1. Create a transparent material and assign it to your objects:

   

2. Enable freestyle in Render settings:

   

3. In Render layers, set the line visibility to QI range and set the end to 1:

   

   Think of the QI range like a sort of depth index; faces directly visible to the camera are 0, faces behind those faces are 1, faces behind those faces are 2, etc.

   By only rendering lines on faces between 0 and 1 (inclusive), you can get a result like in your example image.

---

Or you could use wireframe materials:

See this question for details.

Answer 2

Using blender internal you can set the material type to wire and it will only show the wireframe of the object.

For cycles there is a wireframe node that you can input into a mix node to define transparent areas but it will show a triangulated wireframe.

An option that is available in both renders is the wireframe modifier. This modifier was added in 2.70 and gives you control over how thick the wireframe will appear.

Answer 3

There are several ways to do this.

First: Using the Cycles render engine, this is now extremely easy. You can use the node setup below, with which you can control how opaque the faces are, and the color of the edges.

Another easy way to do this, is to use the Wirefame modifier.

This will alter the mesh to show a mesh along the edges of the base mesh, and will not render any faces. This works in viewport, BI and Cycles. Notice that you may need to get a more recent version of Blender depending on your current build.

Answer 4

Another option would be to make your item from modeled wires, and use that, instead of a texture.

The way to do this is to first create a "wire" from which to construct the wireframes. In the illustration below, I created a cylinder with 8 vertices, and unclosed ends (numbered "1" in the screentshot:

A material (black in this case) was assigned to the "wire", and it was duplicated, rotated, and the length of the cylinder was changed the length to create a 3D representation of the original image. Analyzing the blend file from which the screenshot was created,

https://www.dropbox.com/s/awgnd3acubwou8v/blenderwireframeanswer.blend?dl=0

it will be seen that the "wireframe" will show up in a render, because the wires are meshes, and not blender edges.