How to select desired region for extrusion?

[Anonymous]

I am doing some weight reduction on a plate and am confused about how to select the specific regions that I've created in sketch. I have a sketch with a bunch of slots, circles, and rectangles , and I want to cut out the regions not enclosed by these shapes. Currently, when extruding it selects the entire region within the sketch (including slots, and rectangles) and I can't deselect these regions. 

I've attached the model below, thanks for the help. 

Inventor 2018, Windows 10

[jhackney1972 · Accepted solution]

I am not sure I selected all the correct regions but your part is attached in Inventor 2018 format.  I approached it by using the overall to cut then using the same sketch to add material back in.   I am not sure what you want to do about the half tapped holes.

I zipped the part since the forum sometimes has a hard time with attachments.

[Anonymous]

Thanks! The part you've attached isn't really what I'm looking to do but I've attached another part that might make it more clear as to what I want to cut out. Each of the X marks is a section that I want to cut out of the plate.

But I think I'm trying to understand why I can't select the certain regions to extrude. Is there a way to close the loops on the intersecting lines? I've seen some videos in SolidWorks where it seems like the closed loops are automatically formed and can be extruded easily. Maybe there's a better strategy for creating these sketches that I don't know? 

[TheCADWhisperer]

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@Anonymous wrote:

.... Maybe there's a better strategy for creating these sketches that I don't know?  

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I would model quite differently in SolidWorks or in Inventor.

Can you answer some questions about your Design Intent?

[TheCADWhisperer · Accepted solution]

I try to use obvious symmetry about the Origin whenever possible.

I rarely duplicate any dimensions.

I have never used a zero (0) dimension in Inventor or in SolidWorks.

I mirrored part of the cut feature, but it probably would have been better to simplify the sketch in the first place and then mirror the cut feature (no need to duplicate sketch symmetry on both sides - extra work - extra complexity).

Also, in Inventor sketching - note the Split tool as you will need it.

Edit:  Hmmm, now that I have gone through the geometry - I think I would use the Grill command instead.

[kelly.young · Accepted solution]

Hello @Anonymous I see that you are visiting as a new member to the Inventor Forum.
Welcome to the Autodesk Community!

There are many ways to draw sketch lines and constraints but it all depends on the final product and it's use.

Although best modeling practice says always have fully constrained sketches, if it is a one off that you know won't change in the future, an easier method would be to use Trim.

It will leave you with dimensions needed all over the place, but will help in closing out loops. You can press X to access it by default (or setup your own keyboard shortcuts at Tools > Customize > Keyboard) and can click-hold-drag for easier cutting. 

You can also use Split to break the line in two and can then come back and add a Collinear Constraint to keep them in line. 

Here is a short screencast showing the technique.

Once you have it all trimmed or split you can re-add dimensions and constraints to lock it in better.

Be aware of impossible to manufacture pockets, come back in and add a Fillet to clean up the intersection.

If the part is symmetric you can just draw half and mirror to save some effort.

Hope that helps!

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