Hi bemfarmer,

> I have been unable to twist or warp a Planar rounded rectangle
> derived from a NON-Solid rounded rectangle, after several dozen tries.
> Cannot seem to get rid of the extra control points.

Could you please post the file with your rounded rectangle in it that you're having a problem with?

One particular thing to note with this method described previously is that the thing you actually warp is a surface that you construct from the curve. Either draw in a plane surface and trim it with the curve or use the Construct > Planar command to build a planar surface from it.

Once you have that surface you delete the curve and then select the surface and turn on its control points with Edit > Show pts and manipulate those 4 surface corner points.

See these previous links for some illustrations and additional explanation of this method:

http://moi3d.com/forum/index.php?webtag=MOI&msg=1588.2
http://moi3d.com/forum/index.php?webtag=MOI&msg=909.5

If you're still having problems please post the 3DM file with your geometry in it so I can see where in particular you may be getting stuck.


> Ended up with several circles on the chain link... because ?...

You mean the edges inside of the chain link? That's most likely because your path curve is made up of several sub segments. If you select your path and use Edit > Separate it will break it apart into individual segments and you should see that each segment of your rail path corresponds to one piece of the generated sweep.

That's not really anything to be worried about - that's normal to have a result like that.

- Michael

Thank you very much Michael.

WHOOPS, the 4 control point handles for the Planar, made from the rounded rectangle, were outside of my viewing screen.
Running ShrinkTrimmedSrf command moved them to be tight to the rounded rectangle Planar.

So the method :Create rounded rectangle, Planar, Delete rounded rectangle, ShrinkTrimmedSrf, Show points, Rotate 2 of the 4 control points 90 degrees, Sweep a circle,
works just fine!

This has been an excellent learning experience.

There is more than one way to do it.

May try to make some rope, like a dogs chew toy, with these, and similar methods...

Hello Michael,

I have a problem, if you take a look at the attached file you will find a surface (which is part of a Cylinder's lateral surface) when I use the Show_Pts command it shows control points of the original Cylinder. how can I have control points only for the surface I trimmed?

Hi Psygorn, select the surface and then press the Tab key and type ShrinkTrimmedSrf and push Enter.

If you want to make a surface that will smoothly deform though you may want to prepare a custom surface rather than the default cylinder - draw a circle then run Rebuild on it and extrude the rebuilt curve.

- Michael

Hi Michael, thank you for letting me know of ShrinkTrimmedSrf command.

However, I still have struggles to achieve what "Andre Samardac" achieved years ago in this video:

https://www.youtube.com/watch?v=PCAmSO8qW00&list=PLdnZa7Wc7RKAXiXgjW9pm1sdvQmjSPIq4

If you take a look at the attached file you would see that "blend" doesn't work as smoothly as Andre shows and it doesn't work good for the other object. (Select the red edges and operate Blend command) then you would see at the bottom corners there are issues for the Cylindrical shape and for the other object it is more problematic.

Note: I made the Cylinder by creating a circle then rebuilding the circle and Extruding it.

Also I have below Questions:

1- when the smaller surface is selected and I press "Show Pts" and then "Add Pt" could I have control over how many control points would be added? I mean could I determine how many rows and columns of control points would be added?

2- Does rebuild work on control points of a generated surface? ( for example a surface generated by loft command? )

- Psygorn (Drillbit)

Hi Psygorn, if you want to shape objects by moving surface control points around you would probably be better off doing that in a sub-d modeling program rather than in MoI. Sub-d modeling is specifically oriented around that type of modeling process.

re:
> If you take a look at the attached file you would see that "blend" doesn't work as smoothly as
> Andre shows and it doesn't work good for the other object.

Blend doesn't work well when you give it a sharp corner to go across.

Note that Andrei structured the objects so that the bottom edges are already touching and does not need a blend in that area, while yours has empty space in that area with sharp corners that you're trying to blend across:





Another thing that is problematic about your configuration is that you're not giving enough empty space for a blend surface to fit. Compare these areas between yours and Andrei's:





Blend needs more space than what you're giving it, with a too narrow space it's going to generate a stressed and bunched up surface.

re:
> and for the other object it is more problematic.

There is again the problem where you haven't given enough space for blend to make a connection that is both smooth to each side and also has space to be relaxed instead of bunched up on itself.

If you want to make a model that looks like it's melted and smooth throughout and can be adjusted by pulling points around then sub-d modeling is a much better fit for that.


> 1- when the smaller surface is selected and I press "Show Pts" and then "Add Pt" could I have control
> over how many control points would be added? I mean could I determine how many rows and
> columns of control points would be added?

Not very precisely - you can control whether only rows or columns will be added by setting the Direction option to either "U" or "V" instead of both.

Sub-d modeling allows you to have much finer grained control over the point structure because you can add in single points where you want instead of needing an entire row or column to be added which is how NURBS surfaces work.


> 2- Does rebuild work on control points of a generated surface? ( for example a surface generated by loft command? )

No it currently only works on curves, not surfaces.


- Michael

Maybe variable fillets can be used...

Hi Michael, Thank you for your reply.

> Blend doesn't work well when you give it a sharp corner to go across.

Well , I tried several outlines on the Cylinder, I even tried to have a trimmed surface which is in contact with the main surface on bottom edge -as Andree shows- again I was not successful to recreate what he had created.

Maybe Cylinder is not a good fit for that.

Thank you for your reply anyway :-)

I will try to tweak it to see if I get any results!

And I think Blender is one of the most famous Sub-D modeling tools out there. However, I have to say seeing control points in MOI 3D is very thrilling and it creates excitement because U can have even more control over produced meshes and one can see that there is a lot of potential there! And I know I am not a software developer so, it is true I don't have vision of a programmer I just see the potential and it thrills me :-)

For example I made the spoon you see just by using of the control points it is not a great spoon but it is made in almost no time! :-)

Hi Psygorn, MoI isn't very focused on surface control point editing, it's only got very basic functionality in that area.

The reason for that is that NURBS surfaces are constructed out of a regular grid of points made up of rows and columns. This means you can't just add in a single control point to a surface to tweak a local area of it, you can only add in an entire new row or column of points.

Sub-D modeling was created to avoid that limitation, in sub-d modeling you can add in a single point and it will automatically smooth all the polygons that are connected to it.

So if surface point modeling is what you want to do for a particular model, you would be better off doing that in a sub-d modeling program that has a lot more sophisticated features for surface point sculpting.

CAD modeling is strong in different areas than that, it's great when much of your model can be defined by 2D profile curves and booleans.

- Michael

Thank you PILOU

Hi Michael,

Ok, I got it! :-)