I used boolean diff to create this. What is the mtehod to close it?

One possible method



But seems your original object has some glitch because a Boolean Diff should give closed result!
And not give the same result that this one with rounded profiles

There is a curve/surface mismatch on the left side, so that the left curve cannot be joined...or swept.

Also the little arc on the right does not touch the other curve...

Thanks a lot. Is it bad that rails are from two pieces or it should be as a one piece of edge.

Hi bartosh, your object is not closed after the boolean because the base object you are cutting is not a fully closed solid - it's got a few areas in it where some edges are not joined to their neighboring ones, so it is not forming a completely closed solid volume.

The booleans are mostly oriented around working with solids - when you cut a solid with a surface like you are doing it will leave the imprint of the cutting object behind as well. But when you cut an open surface you'll get different behavior.


It looks like there is a little misalignment between some pieces in this area here, you have to zoom in a ways to see it:





There's kind of a little tiny shelf in there and it's in that area that some of the edges are not joined to one another which is why your base object is not a solid but being treated as an open surface instead. When you select the base object you'll see that it's type indicator in the upper-right area of the properties panel (the place that gives some information about the selected object) reads as "Joined srf" rather than "Solid".

So that part of the object may need to be reconstructed to be all uniform and not have any gaps or things like that, then once you have a solid your boolean difference would leave behind the cutting surface to close off the hole automatically.

- Michael

Also you can see some more alignment problem here - the extrusion part was formed from a slightly different profile shape than the end of the revolved part, could be some problem like the revolve axis was not quite precisely vertical or located right on the center line, or the profile was not totally flat or something a bit off like that:





- Michael

Also another thing to watch out for is these profiles here are not smooth to one another - you'll want to pay special attention to the first and second control points when you're drawing a curve that will be mirrored so that those 2 points are horizontally aligned with one another so that curve tangent is also horizontal and won't form a kind of small kink in the shape when mirrored. The bottom part is smooth though:



- Michael

Hi Bartosh, I've attached here a reconstructed version of your object which has the pieces aligned, it should now behave better when you do the boolean difference, the cutting object will leave its "imprint" into the base object sealing up that hole area automatically.

I rebuilt this by extracting the edge curves from the flat face, tuning up the control point alignment that I mentioned above so it was smooth on that upper part, then extuding that, then using the edge of the extrusion to do a 180 degree revolve, then boolean union of those 2 pieces and also with the bottom knob which I had also extracted out.

Somehow during your construction you ended up with a slightly different profile shape for building the revolve portion versus the extrude portion... Make sure when you're picking things like revolve axes that you have snaps turned on including "Straight snap" so that you can easily get exactly vertical and horizontal lines.

- Michael

Hi bartosh, one other quick note - when your cutting object is only curved in one direction and straight in the other direction you can just leave it as a 2D curve instead of building it out into a surface and use the 2D curve as the cutting object in the boolean operation.

The booleans will automatically extrude out 2D cutting curves inside their own calculations, that can save some steps.

You only really need to build a full cutting surface if your cutting surface is more complex like if it curves in multiple directions and needs to be created by a sweep or something like that.

- Michael

That's a really interesting model. I had to try it with metal flake paint for fun. Click image to enlarge.

Ed

Thanks a lot once again. You are very kind for freshman ;)

Now I can see that my first work in Moi was messy, I need to do it more tidy next time whithout errors.

Is there any easy way to fix alignment of edges or it should be re-make from beginning?

Hi Bartosh - in a case like this it's kind of easier to remake it from the beginning, but I've actually done that for you already above - the remade version is the file attached to this message here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=5811.12

- Michael