model this??

[Anonymous]

Just a bit intimidated by this spiral helix rail.
Anyone have any suggestions on how to model this?
Is there a video out there that shows the process?

I'm thinking rotating while elevating an extruded profile, but I don't think it's possible, is it?

[David Collins]

Very doable with a morph profile following a morph 3d polyline with the tube command from the pet palette. What works best is to create the profile in plan and rotate up and into the start position. Then create a 3d path as a segmented morph line starting from one of the nodes of the profile. The more nodes you have the better it will look. Here it looks like you could draw the path in plan with a node at each stair tread, then set the height of each node in 3d based on the riser height. Note that the first segment of the 3d path has to be flat, after that it can start to rise. Here's the real trick: select both the profile and the 3d line and do a morph/union so that they become one morph. Now you can extrude the profile along the 3d path and it will easily find the nodes.

Edit: I said "very doable." What I should have said was "barely doable with a lot of swearing." Somebody should write a Morph Book.

Further edit: Setting the heights of the 3d morph line nodes turns out to be a pain. In the past I've given up on raising the node heights (after the first node it seems you can't constrain the movement to the z axis) and resorted to placing temporary morph "sticks" with the proper height, which gave me a node I could reliably find and attach the 3d line node to. There's got to be a better way, though.

[Anonymous]

Great work David!
I have six days before having to submit this design proposal for HOA approval. Doing the as built model first and then the addition design in a couple of days. Will just have to work around the stairs for now, won't be modifying those, but it would be nice to get them in the model along with the bolder rock fountain. Perhaps while I'm working on the design proposal someone will be able to steer me to a step by step video of this rail being done? I think with a bit of time and effort I can create some morph bolder/rocks and get them placed.
Worst case scenario - leave these spaces blank and hand draw on the elevations.
Definitely need a morph book:-)

David wrote:
Very doable with a morph profile following a morph 3d polyline with the tube command from the pet palette. What works best is to create the profile in plan and rotate up and into the start position. Then create a 3d path as a segmented morph line starting from one of the nodes of the profile. The more nodes you have the better it will look. Here it looks like you could draw the path in plan with a node at each stair tread, then set the height of each node in 3d based on the riser height. Note that the first segment of the 3d path has to be flat, after that it can start to rise. Here's the real trick: select both the profile and the 3d line and do a morph/union so that they become one morph. Now you can extrude the profile along the 3d path and it will easily find the nodes.

Edit: I said "very doable." What I should have said was "barely doable with a lot of swearing." Somebody should write a Morph Book.

Further edit: Setting the heights of the 3d morph line nodes turns out to be a pain. In the past I've given up on raising the node heights (after the first node it seems you can't constrain the movement to the z axis) and resorted to placing temporary morph "sticks" with the proper height, which gave me a node I could reliably find and attach the 3d line node to. There's got to be a better way, though.