3d vs 2.5d, is it well defined?
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3d vs 2.5d, is it well defined?
I am not sure that I understand the difference between 2.5D milling and and 3D. Is there a clear difference, or is the difference as fuzzy as my understanding?
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Re: 3d vs 2.5d, is it well defined?
The big difference is that on 'real 3D' you can undercut features or make holes that are not vertical.
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Shapeoko 2014F: 1000mm X/Y, 300W Quiet Cut spindle, Arduino Uno/G-shield and GRBL 0.9i
15x30 drag chains, custom spindle mount, 9mm belts, 8mm endplates, 6mm motor plates.
Re: 3d vs 2.5d, is it well defined?
Basically, you can do 2.5D with a 3 axis machine, and 3D with a 4 axis (or more) machine.
As mentioned by GadgetMan! 3D allows undercut.
But you can achieve 3D milling with a 3 axis machine by turning the piece being milled (with fixtures for instance). But it requires more work and precision.
As mentioned by GadgetMan! 3D allows undercut.
But you can achieve 3D milling with a 3 axis machine by turning the piece being milled (with fixtures for instance). But it requires more work and precision.
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Kress 800, Z Axis upgrade, dual Y, 600mm X&Y rails, metal spacers and V Wheels, home switches, 4th axis
Goko - Free CNC Control Software - http://www.shapeoko.com/forum/viewtopic ... 380#p44380
Re: 3d vs 2.5d, is it well defined?
The way I define it when I am talking about CAM software (and have always heard it defined) is that 2-1/2D means making flat bottomed pockets and profiles.
3D means full surface profiling. Not undercuts.
Doing undercuts requires a 4 (or more) Axis machine, but is still called 3D.
3D means full surface profiling. Not undercuts.
Doing undercuts requires a 4 (or more) Axis machine, but is still called 3D.
Re: 3d vs 2.5d, is it well defined?
In general 2.5D is a sub domain of 3D. Roughly, 2.5D we have the complete control over X, Y and but half control over Z axis. In milling it is physically impossible to reach certain regions (undercuts), along Z axis, given we have material left towards the bit.fishtoprecords wrote:I am not sure that I understand the difference between 2.5D milling and and 3D. Is there a clear difference, or is the difference as fuzzy as my understanding?
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Re: 3d vs 2.5d, is it well defined?
I'm with twforeman on this one. 2.5D is to 3D like a poster print is to a full color print. With 2.5D, you can have features at various depths, but all have flat tops and bottoms. With 3D, you can have arbitrary shapes (although only a subset can be milled on a 3-axis machine). A 2.5D object can be described by a small number of 2D drawings, each corresponding to a set Z depth. A 3D object requires a true 3D file format.
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Re: 3d vs 2.5d, is it well defined?
I always thought it was as twforeman and cvoinescu describe it. You can also do shallow undercuts on a 3 axis machine using a ball end cutter with a smaller shank than the ball.

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Re: 3d vs 2.5d, is it well defined?
-Edward
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Re: 3d vs 2.5d, is it well defined?
Good one! 

Re: 3d vs 2.5d, is it well defined?
Awesome.
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Shapeoko# 3456, Makita RT0701c. Stock size for now but have 13"x13" travel by trimming down belt clamps and lip on smooth idler. Dovetailed wooden track clamping setup. Dust shoe in works.
Shapeoko# 3456, Makita RT0701c. Stock size for now but have 13"x13" travel by trimming down belt clamps and lip on smooth idler. Dovetailed wooden track clamping setup. Dust shoe in works.