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Tool path parameter expressions - possible bug??

Message 1 of 12
344 Views, 11 Replies

Tool path parameter expressions - possible bug??

I think I may have found a bug.

I was editing my tool path parameter expressions and noticed this entry_angle doesnt report the value its supposed to.

I havent tested with other tool paths, just this Face tool path for lathe.

The lead in value on the Linking tab, I wish to utilize the lead in angle in a calculation on Radii tab.

As you can see in the picture below, the value of the lead in angle should be 80, but when entered into the expression editor, its being reported as 3.14961.

Is there some conversion going on?






Edit: Looking further, it looks like its converting the angle value into metric mm.

Doesnt make sense to me for an angle, but maybe for programming ease. It may also be an overlooked bug.



Edit Again....

Trying to make some math calculations and angles seem very confusing to me.

For example, a simple

Math.cos(45) returns "0.020682 in)

This doesn't seem to be DEG or RAD.

Can someone help me out with what this is being calculated as?



Message 2 of 12
in reply to: changedsoul

the outer radius of the crop and the inner radius of the crop must be strictly on the surfaces. Maybe this will help you

Message 3 of 12
in reply to: RoccoHilton

Sorry, No this doesn't help me at all. 

Im trying to understand the expressions, not where the inner and outer radius are supposed to be. 

Message 4 of 12
in reply to: changedsoul

That certainly does look wrong. Are you able to record a short video showing the steps you're taking?



Message 5 of 12
in reply to: jeff.pek

I can try and remember how to do that screen record thing. 

Basically i just selected a lathe facing tool path, went to tool path tab for selecting radii boundaries and tried to enter a formula using the lead in values from another tab on the same tool path. 


Ill post back a video if i can figure it out. Might be a few hours until i get to work and try it. 


Message 6 of 12
in reply to: changedsoul

Looks like you're trying to use `entry_angle`, which is an angular value, to the offset, which is a linear value. That would need some sort of conversion to be applied to convert the angle value into an appropriate linear value.



Message 7 of 12
in reply to: changedsoul

Do you want something like "Math.cos(entry_angle)"?


Message 8 of 12
in reply to: jeff.pek

I was actually trying to limit unwanted small movements by calculating a start point based on lead in angle and length. 


For example if lead in angle was 45 and lead in length was .015

I wanted to do 


But using expression variables instead. 

But the math returns results i cant understand. 


I would expect 

Math.cos(45)*.015 = .0106

But its some value i cant see how it gets. 

Message 9 of 12
in reply to: changedsoul

Angle values in expressions are interpreted to be in radians, not degrees. So that's why Math.cos(45) doesn't give you the answer you expect.

Message 10 of 12
in reply to: jeff.pek

If that were true I wouldn't be so confused.

cos(45) should be .707 yet i get 0.02068

Ok, maybe the angle needs to be in radians first.

45*(PI/180) = .7854

cos(.7854) should be .707 but I get 0.0278.


My brain is not clicking on what is going on here.

Message 11 of 12
in reply to: changedsoul

It's possible that what you're seeing is unit conversion (mm -> in) happening when the value is presented, rather than a change in the actual value. Since cos(angle) is a ratio, applying the unit conversion probably doesn't make sense.



Message 12 of 12
in reply to: jeff.pek

It give a strange answer whether or not you convert it though, thats my point.

Unless I am missing something, I dont see how you can get the correct answer for Math.cos(45).....


Ok, well while I was typing this, I am working on another lathe project and it is working on this project the way I expect:

"Math.cos(entry_angle*PI/180)*(entry_distance)" = .0106 (As I was expecting the other project to display)

Only difference is the X axis on the one that doesn't work is pointing towards the Back plane, and the one that works is pointing towards the Front plane.


Is this intended behavior?


Edit: Ok, now I am loosing my mind. I opened the project that was not working and now it is working. I dont know what I was doing. Seems I had an ID10T error.

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