Single twist steel rod and bar...

[Steven Kenzer]

Hi, All. I need to create this twisted steel detail on some furniture I'm working on but not sure how to go about it. Can someone point me in the right direction to do this in regard to tools and technique? As always, thank you for any help on this.

[Kevin Allen]

Use the Twist option in the Deform Tool. You'll need three extrudes of the square rod. Twist one, and Use Model>Add Solids to put the three together. It might be possible to use one extrude and just twist the one area, but I'd have to check that functionality.

[Steven Kenzer]

Thank you, Kevin. I'll check this out later, Much appreciated.

[Pat Stanford]

Similar to Kevin, I would make an extrude that is the length of the twisted part and use the Deform Tool to twist it. Then I would use the Push Pull Tool to extend the end faces to get the correct length.

 

This saves the having to add solids step.

 

[Steven Kenzer]

Hi, Kevin and Pat. I"m still having trouble creating the desired form and wondering if you could elaborate a little on proper technique here. The Deform tool is one I don't have much experience using. I extruded the rod and then selected the end with the deform tool. As I rotate (twist) it does this within itself so really nothing changes. How does one end up with the screw like spiral I'm trying to achieve? Thanks again for any help on this.

[Kevin Allen]

My first though is that the original spiral looks like the extrude was a rectangle, so the twist is visible. With the extruded circle, the twist has no visible effect.

[Steven Kenzer]

Thanks, Kevin. I see now. The square extrusion is not a problem. I needed to do this on both a square extrude and a rod-like one. I might be able to get away with adding the square twist to the rod extrusion..will take a look at that. Is twisting the rod, with proper appearance, not possible?

[Kevin Allen]

It's the corners that give you the look. IRL, I don't think twisting a round rod will give you the appearance you want. I imagine that in your model and in fabrication you'll have to transition from the rectangle to the circle. IRL, the welds can be ground down to make the transition appear seamless. Virtually, I would add a subdivision element to make the transition, of to make the entire piece. That's appreciably more complex modeling.

[Steven Kenzer]

Thanks, again Kevin. I can work with this for now.

[Kevin Allen]

If you make a Subdivision spherical primitive, you can readily model the transition.

[AlanW]

@Steven KenzerHi, Subdivision will get what you want. Bit tricky until you get to know subdivision.

Twist Metal.vwx

[Steven Kenzer]

Thanks for the file, Alan..that's always helpful.

[Benson Shaw]

OK, lots of ways. Here is a Loft Surface one for the control freaks.

Learned this from islandmon about a million years ago!

 

It's giant. Rescale as needed.

This might better replicate the forge work which can compensate for stretching the metal during the twist by pushing it back together.

For more accurate model, parameters should indicate dimensions of the squared portion of the round bar. Photo shows it didn't thin out.

 

Probably could get similar with:

• Fewer NURBS Curves in the stack with greater rotation each.

• Square corners on the transition and twist NURBS Curves. Fillet after.

       But I didn't test.

 

Same technique applies to the square bar, but easier, because no transition needed.

Stack up the NURBS squares, rotate the middle NURBS enough each lift to make the 180° twist.

Fillet the edges after if desired.

 

Fun challenge!

 

-B

 

 

Twister.vwx

[Steven Kenzer]

Thanks for this Benson.....very helpful.