Flatten top

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gkas
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Flatten top

Post by gkas »

Here's what I'm trying to do (let met know if there is a better way)...

3D Modeling. I have a large round disk shape with a slightly domed top. I want to flatten part of this dome. I created a disk of the appropriate diameter I want to flatten. I set the mode of the disk to SUBTRACT. All well and good. Now, how to I lower and raise this disk above the dome? I want to flatten the top 1/4" of the dome. Is this the correct procedure?

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highpockets
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Re: Flatten top

Post by highpockets »

Am I in the ball park?
Image 445.png
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mtylerfl
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Re: Flatten top

Post by mtylerfl »

If John’s (highpockets) example isn’t what you are trying to describe, then please make a hand drawing of what you want and post a picture of it here. I’m certain it’s very simple to do, but a drawing would help us help you! (Unless John has already nailed it, that is!)
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gkas
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Re: Flatten top

Post by gkas »

If you flattened the top dome, then yes.
Dome.JPG
I want to flatten the top third off the dome, basically slice it off a third of the way down. I thought of setting a thick disk down from the top, then putting the disk in subtract mode.

I guess I'm trying to figure out how to subtract a 3D shape from a 3D shape. ie; drop a cube into a sphere. The cube would be lowered into the sphere a third of the sphere height. I can figure how to draw the shapes and use the combine modes, but how do I extrude a shape and suspend it 1" from the floor.

Another example from another thread would be connecting a length 1" square rod to a length of 3/4" round dowel. A round tenon protruding from larger square stock.

Am I making sense?

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highpockets
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Re: Flatten top

Post by highpockets »

Here's how I did it. The problem with your way is in Vectric you can have undercut areas.

The other way to do it would be to subtract a plug from the dome then merge a cylindrical component.
Image 446.png
Image 447.png
Image 448.png
Image 449.png
Image 450.png
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highpockets
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Re: Flatten top

Post by highpockets »

LOL!!!
OK here's a fun way (that cat again).

With the dome as a start.
Get the height of the dome
Draw a square vector slightly less than the diameter of the base of the dome. Make sure it's center of the dome.
Create a shape using the square vector, Flat Profile, Base Height of Dome height minus .25"
Use the Measure tool with Model Cross Section checked.
Draw a vector through the center of the dome longer than the dome.
This will create a profile of the dome and square showing exactly where the square touches the dome.
Now create a circle the size of the points where the square and dome meet.
Use the circle to create a shape using the circle vector, Flat Profile, Base Height of Dome and Subtract Mode
Duplicate the new Component
Set the Combine Mode to Merge
Image 456.png
Image 455.png
gkas, PM me your email address if you'd like the crv3d file. It's too big to attach (even zipped).
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highpockets
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Re: Flatten top

Post by highpockets »

Damn cat!

Dome, use Slice Visible Model, Set Slice thickness to height of Dome - .25". Keep Slice 1
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gkas
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Re: Flatten top

Post by gkas »

Thanks, I got both methods to work.... But I'm still not positive why the first one does. I think I have to study the MULTIPLY mode. I don't think it's uses are as simple as the name implies. I'm definitely going to have to roll this around in the noggin awhile.

Thanks again...

Gerry

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gkas
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Re: Flatten top

Post by gkas »

I did use example #2 to slice the top off the model. The Material Setup was complaining that the model was too thick for the stock. I'm using a 2D pocket as my last step to remove that material. Setup was real happy after I sliced off the top of the model where the pocket was going.

My extra bonus was your mentioning "Use the Measure tool with Model Cross Section checked.". That is a FANTASTIC option that I had not really noticed before. It sure simplifies a lot of calculations. :D

thanks again....

Gerry K.

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Re: Flatten top

Post by WNC_Ed »

John,
That was a +1 , +1, +1
Thank you both - very educational.
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highpockets
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Re: Flatten top

Post by highpockets »

Option two was fun to do and the Model Cross Section is a great little tool that's hidden away. But I prefer Option 3, it's much easier to just Slice the model where you want it.
John
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