[rjmorel]

Why is it when I have a part drawn by doing a 2D wire frame, then using that shape to make a plane , then extruding that plane up .25 so I have a solid part .250 thick the shape of the wire frame all is well. Then when I make a solid cylinder and position it over the part where I want a hole to go thru and do a Boolean subtract it does it but I can see inside the guts of the solid part like it is just a balloon shell?????
If I do the same steps only using the primitive solids like make a solid square, then put a cylinder thru it and Boolean subtract it, the new hole will have a surface around it like a real hole like it is suppose to ???
Any ideas??? I know BobCad doesn't make true solids, but why does it do it the right way with the primitive shapes but not my part shape?
Where this is causing me problems is when I save it as a .stl file for the 3D printer, when it prints the part out it ignores the holes and and prints across it like there are no holes.
thanks, rj

[BurrMan]

Why is it when I have a part drawn by doing a 2D wire frame, then using that shape to make a plane , then extruding that plane up .25 so I have a solid part .250 thick the shape of the wire frame all is well. Then when I make a solid cylinder and position it over the part where I want a hole to go thru and do a Boolean subtract it does it but I can see inside the guts of the solid part like it is just a balloon shell?????
If I do the same steps only using the primitive solids like make a solid square, then put a cylinder thru it and Boolean subtract it, the new hole will have a surface around it like a real hole like it is suppose to ???
Any ideas??? I know BobCad doesn't make true solids, but why does it do it the right way with the primitive shapes but not my part shape?
Where this is causing me problems is when I save it as a .stl file for the 3D printer, when it prints the part out it ignores the holes and and prints across it like there are no holes.
thanks, rj

That would be an indication that one of the objects is not solid. It could also be something like normals inverted on one of the objects.

Can you attach a file to look at. That would help iun giving you an answer.

I know BobCad doesn't make true solids,

Not sure what you heard or are referring to, but BobCads solids are solid/manifold. There is nothing wrong with them. Can you elaborate?

[rjmorel]

That would be an indication that one of the objects is not solid. It could also be something like normals inverted on one of the objects.

Can you attach a file to look at. That would help iun giving you an answer.

Not sure what you heard or are referring to, but BobCads solids are solid/manifold. There is nothing wrong with them. Can you elaborate?

Not solid as in not like a solid in Solid Works where the solid contains all the gobble de goop for stress analisist, what material solid is made of, etc.
If I draw a 2d frame, make it into a plane, then extrude it with caps, is it not a solid ?
I'm sure I'm missing something cause when I try using primitive solid it works fine and I end up with a solid the way it should be. When I draw 2d frame, extrude, it's just a shell.
My 3d printer is telling me normal are facing wrong way. What the heck does that mean????

[Machineit]

The solid is made up of different surfaces. Go to "Utilities" and choose "Reverse Surface Normals." Look for all of the arrows or lines to be pointed the same direction. Click on those you wish to change or reverse.

In most operations it does not matter, but it may in the way you are machining.

Mike

[BurrMan]

When you extrude your 2d wireframe, if it is a closed shape, it will extrude as a solid. If it extrudes as just "walls/surfaces", then the wireframe is open at some point. If you attach a file then we can look.

not like a solid in Solid Works where the solid contains all the gobble de goop for stress analisist,

Well, BobCad doesnt do stress analysis, but it's solids can be used in a package that does that. They are valid.

[rjmorel]

If I pick the wireframe using the shift key, all of the frame turns red so I thought it was all connected together and not broken.
I'll try and get the file attached and show you .Gotta get to ups with a shipment though first. Thanks, Rob

[rjmorel]

here's the part: NOT
Well when I try to save the part as a .dwg or dxf for the attachment BobCad shuts down so how do I get my part file onto here thanks rj

[BurrMan]

Save it as a bbcd file and then right click it and choose send to-compressed zip and attach the zip.

Chain selection has a tolerance setting. The other thing that would do it is "non-planar" or overlapping/generally buggard up geometry.

[rjmorel]

here's the zipped file cept I made it 1" thick instead of .250 to better show the hollowness I'm talking about, rj

[Trotline]

I didn't spot any obvious geometry issues. I extracted the edges of the two hole circles in the plane of your profile geometry, selected the profile as well as the two circles when making the planar surface, which generated the surface with the holes already in place, then extruded that surface, and had no issues with "hollow" solids. I don't know if there's a reason you wanted to boolean subtract the holes, but that's a workaround that should avoid the issue altogether. Hopefully others will actually locate the problem for you.

Luke

[SBC Cycle]

+1 on the post above, it might be easier to extrude the shape with the "holes" already in the 2D wireframe.

That said, you have a geometry problem. I extracted the bottom edge of your profile and tried to "chain select" it. The gap just pops out at you when you do that.

Attachment 184950

Zoom in at the ends of the selection and you will find the gap. Burr is correct once again, it is not a solid.
EDIT: There are several gaps in the same general area. It looks like you had some tiny fillets in there that got lost somewhere.

Now, THAT being said, you will get that sometimes when the surface normals aren't pointing "out" of the solid like they should.

[SBC Cycle]

If I pick the wireframe using the shift key, all of the frame turns red so I thought it was all connected together and not broken.
I'll try and get the file attached and show you .Gotta get to ups with a shipment though first. Thanks, Rob

I just spotted this post. There wasn't anything in your original file except the solid. Take a look again at your original wireframe. As Burr was implying, if the gap is smaller than your chain tolerance, the software will select it all even if there is a gap.

[Trotline]

That stared me in the face, and I missed it. I extracted all the edges, and saw the break, but since it didn't show in the original profile, I dismissed it as an artifact of extraction. I should have known better. Good catch.

Luke

[jrmach]

I had no issues at all .This is how I did it.Extracted from single the top surface.Then went to extrude curves,,shift click profile,,then pick each hole,,right click ok,,and done.What am I missing ?Either it works because of the way I choose my work flow or maybe my tolerance settings ?(.001) I got a solid %100.

[jrmach]

I just tried again by using the bottom surface,,extract from single.Although I could not chain select profile,,I picked all geometry and extruded curve and it still worked.

[rjmorel]

thanks a bunch guys. I just put the 2 holes in randomly so you could see the hollowness of the solid part . The holes are actually turned 90 deg from where you see them to put a bolt thru to tighten the clamp. Which is why I didn't include them in the wire frame. I had to make the solid then add the cylinder , rotate and reposition them, then Boolean -. So my problem originates with the sloppy wire frame chain . I'll have to pay more attention to that as I did do a lot of changing and redrawing to get the shape needed.
Trotline ,so you can fix the holes that don't have a surface around them. Can you tell me how? I read you post above but being a noob, I kinda need a tutorial with a click here, pick this , then do that and it should work.
thanks again.
I'm going to save all these replies and print them out so I can reference them next time and hopefully avoid repeating these mistakes AGAIN. rj

[Trotline]

I did a quick video showing the process I described in my earlier post. Let me know if you have any questions.



Luke

[rjmorel]

Thanks Luke, That will help me down the line a lot when missing details like this and then I need to add them, rj

[SBC Cycle]

I just tried again by using the bottom surface,,extract from single.Although I could not chain select profile,,I picked all geometry and extruded curve and it still worked.

I did the bottom surface when I tried. I'm not sure if the little pieces were missing because I got them from a solid that was already deformed. Could be the original geometry WAS fine. Not sure what's up with this one.

[rjmorel]

Would a surefire way for me to avoid all this bad wire frame at the getgo be to draw the shape of the frame. Then extrude the curves around the frame and that would show me any lines that are not connected? Then connect any missing lines together ,extrude them, then planer the top and bottom to make it a solid??? rj