Hi Denman, thanks for posting the models, that really helps!

Yeah for "test2", like Steve and Danny mentioned something happened to "un-solidify" that part, it isn't connected together into just one single solid anymore.

But also notice this area here:




That's where your cutting object just kind of comes very flush and sort of grazes the tire surface. This kind of situation makes things much more difficult for the booleans to calculate.

It's better if you can set things up like this instead:



Here I used Transform / Scale / Scale1D to kind of stretch out your cutting object a little bit so that it has a more definite protrusion through the tire body, that is the kind of thing that will work better for booleans.

I've also solidified the tire body, and set it up to just do half of it and then the results can be mirrored. Also I moved the tire so that it was centered around the origin point, that tends to be a convenient way to position things because it is easy to snap back to that origin point later on.

That base model is attached here as test2_new.zip .


So then the steps to finish it are:

Select the new slightly longer cutter:




Use Transform / Array / Circular to replicate it (looks like you had 45 copies):



Now select the base tire, run Construct / Boolean / Difference, and select all the cutting pieces. With the cutter arranged like this the boolean can be done more easily:




Now to mirror it, select the flat face on the opposite side:



And delete it:



This now has an open edge there, now this shape can be mirrored, and then use Edit/Join to glue the 2 pieces together along that open edge to form the final solid:



- Michael

Hi Denman, and yeah for tire3 like Danny mentioned the issue there is your base tire is not a solid, to get the kind of behavior you would expect from the booleans you want to make that a closed solid instead of an open surface.

Danny showed one way to do that, which is to make your original profile curve to be a closed curve before you revolve it.

That's probably the best way since you probably want your tire to have a kind of slim thickness like that.

Here is another way to show you some other techniques on how to solidify it by building some additional surfaces:


Select this edge:



Run Construct / Extrude. Uncheck the "Cap ends" option, and move your mouse to snap on to the point on the back side, that will extrude out to that distance:



Now select those 2 pieces, and use Edit/Join to glue them together. Now select that joined piece, and use Construct / Planar to turn it into a Solid:



The Construct / Planar command can be used to fill in planar openings in a open object to turn it into a solid.


With your base piece as a solid then the booleans should work a lot more like you would expect - although you can use surfaces in the booleans the typical sense for which pieces are kept and discarded are mostly oriented around volumes, so you probably want to have closed volumes (instead of open surfaces) to get the most sort of "normal" expected results.

- Michael

Thank you very much, manz, Danny and Michael for the helpfull and very fast replys.

This really helped me to understand better how to deal with these kind of bolean operations.
Now I am going to try this all by myself :D

I want to keep participating in this forum so you guys will se me around here. Thanks again.

-Denman

Hi Denman,

I would suggest that you set up a shortcut key to select solids, that way you can check during boolean operations if the model does get broken. It is an habit of mine now, and can save problems as it is easier to check and then make changes if needed.

For the shortcut, go into options/ shortcut keys, and add a key to use and then the script:-

script:moi.geometryDatabase.getObjects().getSolids().setProperty( 'selected', true );


Sorry for my abrupt earlier reply, I was just passing by and just wanted to inform you of the problem,.. I should, on reflection, given you more info.

Regards, and welcome.

- Steve

Hi Steve,
thank you for the suggestion I am definetely going to use a shortcut for that script.

-Denman