I think this is one of the most difficult situations so I would be very glad to hear that it can be done with MoI.

You can explore this possibility
Create a spire3D (a circle sweep along a rail) and use function Array Dir along a curve or Array Dir Circular :)

Another tiny variant:

- Step 1. Make a circular array
- Step 2. Loft the shapes
- Step 3. Build the column with the pieces.

This last step is only for build an "real" column stone by stone. In the virtual world you can build the column in only one piece! :-)

Terrific method! :)

> Terrific method! :)

Hi Pilou, those look really cool. That would make for a pretty crazy temple! :)

- Michael

Hi David this is a great method.

JTB check out the images that David attached - for the circular array he picked the center point of the profile as the center of the array. Normally this would replicate a bunch of objects on top of each other, but with the addition of a vertical step, it will stack the copies up in a column shape. Very good idea David!

The other note that I'd make is that you'll probably need a fair number of sections for the loft, each section will probably need to be rotated by only a somewhat small amount from the previous one.

This is because there is an "anti-twist" mechanism built into loft where it tries to minimize twist between 2 sections. So if you have a symmetrical shape that is rotated in say a larger 90 degree increment from each other, twist minimization would probably produce a totally straight loft. So you need a smaller increment between each section so that MoI won't be able to find a just straight connection between the profiles.

Does that make sense?

- Michael

The other thing that you can do is you can edit the "seam point" of the loft to purposely introduce twist.

To do this, make some vertical copies of your profile curve, like with Array Dir.

Now select them all and Loft, but don't push "Done" to exit the Loft quite yet.

While you are still inside of Loft, look at the viewports - you should see some points displayed in there - these points are showing the current alignment points between each profile. You can go in there and click and drag on those points to relocate the alignment point to somewhere else. If you go an progressively do that to each section you will introduce a twist into the loft. Drag each point a little bit further around in one direction.

Be careful not to click on a loft curve instead of the seam point - if you click on a loft curve (the curves will highlight as you move over them), it will reverse the direction of that curve, you don't want that in this case.

This would allow you to make a somewhat less dense (less points in the surface geometry) twisted column since it would use fewer sections.

- Michael

Very nice techniques, thanks for these tips.

Hi Michael:

>This is because there is an "anti-twist" mechanism built into loft where it tries to minimize twist between 2 sections.

Yes, I noted it. I suppose that it must to look for the optimized number of shapes... :-)

at Pilou.....

as soon as I´ve seen your picture I´ve remind the "churros" (spanish meal with flour, oil and salt....all blended and fried. Fantastic for the breakfast with coffee or chocolate....yum yum yum) :-P

like that:

Damned, that is the best chocolate that I had never drunk ! Churros + Chocolate is the paradise!

I'm getting hungry now... :)

Pilou, I guess you could make a temple to the breakfast Churros with your twisting column!

- Michael

Thank you all, for your ideas...
This question was sent to me from a friend. He also sent me the answer from a 3dsmax newsgroup
Obviously the answer was simple.
The reason I am posting this here, is to show the power of MAX modifiers and why I keep asking/wishing for this kind of modeling history.
I mean, MoI is great, but the modifier stack that Max has, is what we all need.

So, wishlist item :

a "TWIST" command in Construct panel, because it can be very useful.
a "BEND" modifier would be nice too.

I don't know if what I say can be done, or if mentioning MAX is not good.
I would like to hear from Michael about tools like these.
I mean, if they can be added to MoI since they are applied to a solid after it is created. For example, you make the circle and you extrude it but so far there is nothing more to do with it, except boolean ops.
Is there any limitation to further adjustments of the shape?

> I don't know if what I say can be done, or if mentioning MAX is not good.

Hi JTB, it is fine to mention MAX, especially as a way to clarify a feature that you are asking for.

Unfortunately it is a lot more difficult to provide this type of modifier inside of MoI than it is in Max, due to the different types of geometry that are being used.

Max is oriented towards generating objects that are going to be rendered only, instead of manufactured. When it applies a twist or bend modifier, it creates a polygon mesh approximation of your object and then it is that mesh approximation that is twisted and bent. The end result twisted object is a polygon mesh instead of an accurate truly smooth object.

MoI is more focused on generating accurate NURBS geometry with its modeling tools, instead of generating polygon mesh geometry. But this focus makes some things like twist and bend a lot more difficult. To do this in MoI would involve generating an actual accurate twisted object instead of only a mesh approximation result. This is possible but it is pretty difficult to do, I don't think it will be available in MoI anytime soon. It is possible to do this in Rhino V4, so if you need to do this, you could look into getting Rhino V4 and bringing your MoI models into there for twisting or bending. Or just use Max for the twisting or bending if getting a polygon mesh result is ok for your purposes.

Meshes are just a lot easier to deform in this type of a way than a NURBS solid. For a mesh, you just move the points around and that deforms the mesh since the mesh goes directly through the points. For a NURBS surface, the control points of the NURBS surface are not just points on the actual surface geometry like a polygon mesh, they kind of float a little ways away from it. For simple transforms like move, scale, and rotate, it works to transform the control points of the NURBS surface to perform the transformation to the surface as well. But for other fancy things like bend and twist, this is not the case.

- Michael

Thanks a lot for such a detailed answer, Michael.
I guess I have to realize that we need all the tools we can get... MoI is great and I love the simplicity combined with the power of the results but things like Max modifiers are very useful especially for me, a non-experienced user and with everyday need for corrections and changes.
2D tools are important too, so AutoCAD will never die...
My only problem is the money for all this software... My clients never understand I have to keep my tools up to date, my PCs too.
So, as everyone else, I try to use the less apps possible.

I created a twisted array of the shape and then lofted it.