Columns with different endings

[kamild]

Hello everyone,

I have a modelling task which involves the re-creation of columns of a very specific shape.

While their base is a circle, the top part is an ellipse (and in a few cases even some other "organic" shape based on a spline). What more, top and bottom shouldn't be connected with a straight line, but with a certain curve profile. I am attaching screenshots from my tests. So far I was only succesful in creating a lofted morph shape, but that is not exactly what I need, as both parts (base shape and top shape) are circles.

Any ideas for approaching this problem would be appreciated. Thank you!

[Laszlo Nagy]

Which ARCHICAD version are you using?
AC23 has new Column Tools so depending on your version, the answer may be different.

[runxel]

I for myself would always resort to Rhino for this kind of freeform adventures.

However it is possible in Archicad:

Start with the round base as single morph surface.
Use the extrude command from the PET palette.
Only extrude to certain small height, than use the box scale command, but only for the new topsurface.
Repeat until you get to the desired total height.
In the end make all the side curves smooth.

This of course needs some preperation:
Draw the outlines for each direction with the morph line (you already did so in 2d, I guess?), this will act as a guide for your box scale.

I'm not sure, how this is supposed to work with the new column tool, tho. You can't taper something round into something eliptical.

[Laszlo Nagy]

runxel wrote:
I'm not sure, how this is supposed to work with the new column tool, tho. You can't taper something round into something eliptical.

Yes, you can. You just have to check the Width Stretch and Height Stretch modifiers in the Profile Manager Dialog, and you also need to unlock the "Link Dimensions" button so the Width and Height of the Profile can be set separately for both the Top and Bottom of the Segment:


So, he would only have to figure out how many of these tapered segments the Column needs to be composed of to correctly approximate the desired geometry.

[runxel]

LaszloNagy wrote:
Yes, you can. You just have to check the Width Stretch and Height Stretch modifiers in the Profile Manager Dialog,

Ooooohhh, you just made a round profile?
Ingenious!

And also pretty dumb. Because you need to make a profile for that. What a joke! Why can't the normal round beam do this? Preposterous!

Btw: You can't make the seems to be invisible, can you? (Like the "smooth" option for Morphs. Might be a dealbreaker...)

[Barry Kelly]

runxel wrote:
Why can't the normal round beam do this? Preposterous!

The round segmented column can do this.


However as you say the segment lines will show.
Convert to morph and hide.


Maybe look for an object that will do it.
This is an old one i still have in my library.
Search BIMComponents if you don't have the primitive shapes in your loaded library and you will find it.


Barry.

[kamild]

I was already trying "Curve Base 14", but there is no control on the spline profile as much as I need it and also top and bottom are both circles. So no go with that object.

Runxel's recommendation for extrusion may work (thank you), but it will probably be a slow process, I think (without making any tests yet).

Barry, can the "round segmented column" have different shape on top and bottom? Can it start with circle and finish with ellipse?

Thank you,

[Lingwisyer]

kamild wrote:
different shape on top and bottom

You start with two circles, a circular column, then use the stretch modifiers to distort one end of it. You will need to figure out your segmentation manually to achieve a "curved" transition.

[Barry Kelly]

kamild wrote:
Barry, can the "round segmented column" have different shape on top and bottom? Can it start with circle and finish with ellipse?

Sorry, I lost track of your original post.
The object is round only.

If you need something other than circular, then you will have to use a profile in the segmented column.
With a custom profile you can adjust the length and width of each segment.
With a circle all you have is the diameter as it assumes you really do want a circle.

Or you could do a round column and when you convert it to a morph to hide the segments, you can also stretch or shrink it in the x or y axis.
But that will affect both top and bottom.
Using the segmented column with a round profile you can actually control the stretching of each segment individually.


Barry.

[kamild]

Thank you Barry for clear explanation.

This method has a potential of working. As I need those columns not only for approximation, but also as a final visualisation model, I think it will be a process of creating really many, many segments to achieve visual smoothness. But other than that, it should work.