Tutorial: how to model (and render) a realistic spiral cable in Blender (and Yafaray)/1

At work (I’m a Mechanical Design Engineer) I had to render a model of a video intercom to get a realistic shot. I already had all the parts as CAD models, so that I had just to export them in STL format and import each file in Blender. All but the cable.

Even if I’m not a good Blender modeller, I thought that it could be easier (and cleaner) modelling it into Blender than into the CAD software; furthermore I could easier apply modifications to adapt the shape of the cable to the position of intercom body and handset.

The initial stright shape

I started to model the cross-section of the cable, that is roughly oval. So, in the XY plane, I added a circle mesh. Well, let’s call it an octagon, as it has only 8 vertices; I wanted to make it as simple as possible, then I will let SubSurf. make the dirty job. 🙂

I usually consider 1 Blender Unit = 1 cm, so I scaled the circle to be 0.5×0.7 and moved the vertices 0.6 along x axis.

Before generating the spiral part of the cable using the screw tool, I need to add a vertical edge as long as the spiral pitch (I made it 0.7), as showed below:

The vertical edge could be positioned everywhere, but I prefer to put it on the spiral axis because so it’s simple to delete it (them, because the screw tool work on this segment too) after the screw tool has been applied.

Now I’m ready to generate a spiral. I set the Turns value to 10 and the Steps value to 8.

I need 40 turns, so I will run Screw 4 times. Now I can select and delete the nodes along the spiral axis, smooth the mesh and apply Subsurf with levels=2; I also neeed to recalculate normals. This is the result:

To make the tail I extruded the border some times and rotated the section to get a good shape. Then I closed the surface as showed:

Tutorial: how to model (and render) a realistic spiral cable in Blender (and Yafaray)/2>>