Hi xrok1 - use Trim in this case to slice the solid by the curve and divide it into pieces.

I would start by deleting the bottom flat face of the cone underneath if there is one. Then select the cone and run Edit/Trim, select the curve as the cutting object, and then at the next prompt where you can pick pieces to discard, just push Done or right-click to keep all the pieces. Now your cone is divided into 2 pieces by that curve.

Now you can just grab that small piece and slide it out along the y axis, then select the edge around it and the original curve, and do a loft to create the extrusion side-wall part. It is also possible to build this part by using Extrude instead if you want, but you will have to set the extrusion direction.

Then select the 3 surface pieces and use Edit / Join to glue them together. At this point you may want to also delete your projected curve because it will probably get in the way if you want to select edges for filleting after that.

Since you have an open flat base you can cap that off by selecting your shape and use Construct / Planar which will place a trimmed plane along the bottom to seal it into a closed solid.

Let me know if you have any problems following these steps.

- Michael

thanks, that works great, maybe you could add an option to merge the result saving the problem of merging or joining things together after such operations??

BTW what is the reasoning behind needing to remove the bottom of the cone, why can't this operation be done with a solid?

Hi xrok1,

> maybe you could add an option to merge the result saving the
> problem of merging or joining things together after such operations??

It's often times hard for MoI to see the proper pieces to join together.

Like for instance if you use Loft you may Loft between the edge curve of the small cut piece, to the "stand-alone" curve object that was projected on to the cone surface - that is not an actual piece of the cone surface itself. So in this case it would be difficult for MoI to find all the correct pieces to join, some of the pieces are not selected or directly attached to the curves that you are lofting...

That can happen pretty frequently when you're modeling individual surface pieces like this.

It could try to search through the entire scene looking for the piece that is nearby, but that would take quite a lot of slow calculations on a complex model.

But at some point later on I would like to add some stuff to make it easier to to "protrusions" like this that would auto-join though, that may involve selecting the base surface before extruding or lofting, or associating the curve with the surface in some way before doing the extrude or loft, I haven't really gotten that figured out yet.


> BTW what is the reasoning behind needing to remove the bottom of the cone, why can't
> this operation be done with a solid?

Just that one curve does not cut a solid into 2 different pieces, you would need that curve to be closed to do that, meaning you would need to also have the bottom small arc piece that follows along the base of the cone. Instead of messing around with that, it is easier to get rid of the bottom face because if you only have the top cone surface that curve does fully divide it into 2 separate pieces.

It's like this situation:



Imagine trying to cut that box by this line, without any extra projection of the line happening - it won't divide the box into 2 pieces because it only divides the top face in 2, not any of the adjacent faces. The bottom plane of the cone is the similar kind of adjacent piece.

But if you separate that box and only work on the top plane, then that line does divide just that one piece into 2 properly.


Also you will get a cleaner model at the end (fewer edges and surfaces in it), if you build the final bottom as one single trimmed plane, instead of 3 different plane pieces joined together, so that would involve deleting the bottom plane piece anyway.

- Michael

thanks for your answers, i'm not trying to question your motives just understand them so i know that i'm utilizing MOI properly.

i appreciate your patience with what must sometimes seem like annoying questions .

Hi xrok1,

> thanks for your answers,

You're welcome!


> i'm not trying to question your motives just understand them so i know that i'm utilizing MOI properly.

That's what I thought - I'm sorry if I gave any different impression!


> i appreciate your patience with what must sometimes seem like annoying questions .

:) Actually the questions are pretty important to me - they generally help me understand what are the more confusing areas of the software. Sometimes receiving and answering questions gives me ideas on how to make improvements in the future to solve problems that cause the questions to come up in the first place. Of course some types of things are not easy to solve, but it generally is a source of information for me as well.

I also view it as a worthwhile investment for me to spend time answering questions here on the forum, because it can help quite a few other people as well that are browsing through the forum just trying to soak up helpful information.

I'll see if I can come up with an example for your other controller shape a bit later on.

- Michael