Drawing circle cuts hole in plate

jay_williams

I have a square plate (i.e., square shape I've extruded to 1/8" thick). I want to create a protrusion from the surface of the plate. When I draw a circle on the surface of the plate, however, all it does is cut a hole in the plate. My understanding is that I need to draw a circle, then an offset, then extrude that "ring." What am I doing wrong? By the way, the plate is extruded below the plane and I'm drawing the circle on top of the plane.

Thanks,
Jay

Hakro

Hi Jay,
may be this helps ...
After drawing the circle in the Sketch use the Extrude command with following settings:
Solid -> Add -> Blind - Opposite direction

jay_williams

It looks like I'm not even able to get to the point where I can do the extrude. Simply drawing a circle on the plate cuts a hole through it! Why that would happen?

jay_williams

This is what I get simply by drawing a circle on the plate.

_Ðave_

@jay_williams I suspect that you had used the your entire sketch to define the square extrude. Therefore by adding more entities to the sketch the extrude will automatically invoke those entities if possible. This is just a quess, I could give you a more definite answer if you provide a link to your document 

jay_williams

Left a comment in your profile, Dave, but probably should've just put the link here. Part 2 has the issue.

https://cad.onshape.com/documents/3e9dacb5e2033879c501ee04/w/13691e67dc4453b7e9ea7c24/e/797882bb5a9fe84727fae974

derek_ward

You should probably just create a new sketch on the surface of your square plate with the circle instead of using just the one. 

_Ðave_

@jay_williams I didn't seen the circle in any of the sketches. I assume you attempted to place the circle in the sketch named foot.
after creating the circle then open extrusion #1 and add the inner area to the sketch regions list. then just create your new extrusion/protrusion by selecting the inner sketch region only.

_Dave_ 

jay_williams

Dave, I tried what you said and didn't quite understand it / couldn't get it to work. Derek, I tried what you said and got it to work. I still have no idea why I couldn't just add the ring to the plate. In any event, I'm glad I got it to work. Hopefully, I'll understand more of this stuff as I go. Thanks for your help.

_Ðave_

@jay_williams  The below video may help explain.

derek_ward

_Ðave_ said:

@jay_williams  The below video may help explain.

Dave,

Good point.  I forgot that you use one sketch for multiple extrusions.  

jay_williams

Dave, Why did drawing the circles on the sketch create a hole in the plate? Thanks for going to the trouble of creating that video for me.

_Ðave_

I suppose that Onshape could have coded it to extrude any way they wanted. They those the most logical option but apparently not in this case. Therefore you must reselect the desired areas.

_Ðave_