shape profile angle explaination

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TReischl
Vectric Wizard
Posts: 4575
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: shape profile angle explaination

Post by TReischl »

Ok, let's see if we can make sense out of how this thingy works!

First, I am going to start with the following in the dialog box:

Angle: 45 degrees
Base Height : 0
Final Height: No Limit checked

So what happens? A hemisphere is created that is about .2929 inches tall.

Why? Because the Angle setting is controlling the geometry. The diameter of the circle was spec'd by the user as 2 inches.

What is the Angle? It is the TANGENT of the SPHERE with a diameter of 2.00 inches.

This is what it looks like:
C1.JPG
All of this changes when the user starts specifying Height limits.

If Limit to Height is checked and the value specified is LESS than the calculated height, the Top of the dome is cut off to the spec'd height. If the value is GREATER than the calculated height, nothing happens. So the Limit to Height option is pretty simple.

Scale to Exact Height does NOT create a SPHERICAL dome. If it did, specifying a height of 1.00 would yield this:
c2.JPG
But it does not when the angle is anything but 90 degrees, instead it creates this:
c3.JPG
So, in the case of Scale to Exact Height the Angle setting controls the slope of the sides.

John, I hope you understand now why that 36 degree angle I showed earlier is important and why it is relevant. That would be the angle you would need to enter to create a .5 chordal height for a 2 inch diameter section of a sphere. That is also why I wrote that Aspire is geared more for artistic work and that if you really needed to create a 2 inch diameter spherical dome with a .5 chordal height it would be easiest to create it using a sweep function rather than the dome method.

Hope this helps you out!
"If you see a good fight, get in it." Dr. Vernon Johns

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