Trouble building a ramp.

[nweeks]

I am trying to create a helical ramp which has an amorphous shape in plan. I found the video by David Light which does a great job of showing how to create a helix based on a cylinder. I used that method to create a spline which represents the edge of the ramp. The problem I am having is creating a profile of the ramp which is extruded along the path. I want to keep it parallel to the "ground" and it wants to bank like a race track. Seems like it should be simple, but I am stuck.

[robert.manna]

Without experimenting myself, you may need to consider using a generic component to create a profile. The advantage here would be that the profile can be set to always orient vertically, which may eliminate the "twist". Other options to explore would be the use of adaptive components to build the geometry you need. Think about how you might break the geometry down, even if it is meant to be a monolithic form. Lastly, if you go with an adaptive component approach you will also want to investigate the Orientation property of your adaptive points, which will also affect how the AC orients itself.

HTH,
-R

[nweeks]

Thanks for the suggestions Robert. I have attached an image to try and clarify the issue. I have done some of what you suggest trying, like changing the orientation of the adaptive points which define the spline, but it is the point on the spline which is controlling the orientation of the profile, and I can't find a way to change it.

[robert.manna]

Can you post your .rfa file? I have a couple thoughts, but not the time to start from scratch...

-R

[nweeks]

Unfortunately I can't upload the family that I am working on...I guess it's too big (almost 6mb). I have attached the three families I used, but I certainly understand if you don't want to spend time putting them together. The CirclesOutside.rfa is the framework on which I placed the spline - RampEdge.rfa, and the RampProfile.rfa is the profile I put on the spline.

[robert.manna]

I don't know if this will help or not, but here is my approach to your apparent problem. Pay attention to the Orientation setting of the Adaptive Points in the AC being used as a profile (family 3).

-R

[nweeks]

That's exactly the solution I came up with...an outside circle, an inside circle and an AC that I could attach between them and create a form. The reason I am trying to come up with a path is to eliminate the need for the inner cylinder. This method is pretty easy until you get multiple cylinders next to one another and need the frame to be a tighter grid. It gets hard to see where the attachment points are.

Thanks for taking the time to try it out. I apologize for not mentioning I had tried this technique and saving you the time to mock it up. I do think it achieves what I am trying to do, just wish I could find a more efficient approach.

[robert.manna]

Ah, oh well, good practice for me... :-)

As to the issue with the twisted workplane, I've complained before, but been told there is no real good solution. What if the AC for the helix had two lines...? So that you got paraellel lines to drop points onto, then your AC, without having to have two cylinders... The trick would be the orientation property for the AC's adaptive points, but that should be doable, particularly since the cylinder is "normal". I'm thinking you could work with "vertical in project" to get a consistent orientation, that would also work for non normal surfaces, like if your cylinder was wider at the top....

-R

[robert.manna]

I really should've spent the last 45 mins working on other stuff, but this was far more interesting...

[nweeks]

That looks like it works pretty well. Still deconstructing it to see how it works. Looks like you placed a line of Adaptive Points and then used them to host the points making the ramp frame - am I missing something?

Thanks for giving it a try. Very helpful.

[robert.manna]

Yeah, sounds like you're on the right track. Its all about the offset points from the different workplanes of the adaptive points.