Hi mir4ea, that option would actually be better labeled something like "Move profiles on parallel planes".

It will currently only have an effect if there is no scaling rail being used, all profiles are open curves, and both rails are open and are made up of one single segment, and also all profile curves have to be on parallel planes.

When it is activated, instead of using the regular method for sliding the profiles along the rail curves, it instead moves along one of the rails and intersects the other with a plane (using the common profile plane normal) so that all the generated profiles for the sweep are on planar slices. In the default sweep mode when things slide along different length rails it will usually cause the profile curves to kind of bank around a bit instead of staying all in one plane, that banking gives a twisting effect and can make a sort of bulge near the ends.

In the future I think I'll be able to relax some of the restrictions on this mode and rename it to something about using parallel planes.

- Michael

re: Forum search - it seems to be working ok for me, I did a search for "Maintain tangent" (with quotes included), and got various results, there is some more descriptions in these:

http://moi3d.com/forum/index.php?webtag=MOI&msg=2226.11
http://moi3d.com/forum/index.php?webtag=MOI&msg=2908.13
http://moi3d.com/forum/index.php?webtag=MOI&msg=2908.17
http://moi3d.com/forum/index.php?webtag=MOI&msg=3550.2
http://moi3d.com/forum/index.php?webtag=MOI&msg=3761.2
http://moi3d.com/forum/index.php?webtag=MOI&msg=4924.7


If you don't put in quotes " " around your search terms, it will look for any of the words you put in which tends to match a whole lot of stuff.


- Michael

Now I understood!
I look at this picture and can not understand what you sweep and than how you make thiss mirorred object.


I thought that rails lay on the same floor and it confused me. I think the angle of this picture is not very good as may confuse people.
Now I understood it clear and will use it, useful function.

Yeah in that picture there, one rail is flat on the world x/y plane and the other one is vertical. A lot of times it can be hard to see what's going on in 3D without being able to rotate around and look from different angles.

- Michael

"""""""""I look at this picture and can not understand what you sweep and than how you make thiss mirorred object.""""""""""

Looks like a good candidate for "rail revolve". Mirror the bottom rail and join it, then do a rail revolve on the arc, setting the bottom as the rail. No need to sweep and mirror and construct.

Hi Andrei:

here is an example about "mantain tangency" making a simple bike's saddle.
Both sweep examples (-B-C-) using same splines
Also Burr's suggestion with rail revolve instead of sweep.(magenta line is rail revolve axis)



you can see three different results
have a try with my file attached,if not clear

M

(..oopss..forgive me for grammar error..is MAINTAIN..)

Hi m-dynamics,
thank you good example)