#LyX 1.3 created this file. For more info see http://www.lyx.org/
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\layout Chapter

Image-to-gcode: Milling 
\begin_inset Quotes eld
\end_inset 

depth maps
\begin_inset Quotes erd
\end_inset 


\layout Standard
\align center 

\begin_inset Graphics
	filename image-to-gcode.png
	lyxscale 50
	width 100text%

\end_inset 


\layout Section

What is a depth map?
\layout Standard

A depth map is a greyscale image where the brightness of each pixel corresponds
 to the depth (or height) of the object at each point.
\layout Section

Integrating image-to-gcode with the AXIS user interface
\layout Standard

Add the following lines to the 
\family typewriter 
[FILTER] 
\family default 
section of your .ini file to make AXIS automatically invoke image-to-gcode
 when you open a .png, .gif, or .jpg image:
\layout LyX-Code

PROGRAM_EXTENSION = .png,.gif,.jpg Grayscale Depth Image
\newline 
png = image-to-gcode
\newline 
gif = image-to-gcode
\newline 
jpg = image-to-gcode
\layout Standard

The standard 
\family typewriter 
sim/axis.ini
\family default 
 configuration file is already configured this way.
\layout Section

Using image-to-gcode
\layout Standard

Start image-to-gcode either by opening an image file in AXIS, or by invoking
 image-to-gcode from the terminal, as follows:
\layout LyX-Code

image-to-gcode torus.png > torus.ngc
\layout Standard

Verify all the settings in the right-hand column, then press OK to create
 the gcode.
 Depending on the image size and options chosen, this may take from a few
 seconds to a few minutes.
 If you are loading the image in AXIS, the gcode will automatically be loaded
 and previewed once image-to-gcode completes.
 In AXIS, hitting reload will show the image-to-gcode option screen again,
 allowing you to tweak them.
\layout Section

Option Reference
\layout Subsection

Units
\layout Standard

Specifies whether to use G20 (inches) or G21 (mm) in the generated g-code
 and as the units for each option labeled 
\series bold 
(units)
\series default 
.
\layout Subsection

Invert Image
\layout Standard

If 
\begin_inset Quotes eld
\end_inset 

no
\begin_inset Quotes erd
\end_inset 

, the black pixel is the lowest point and the white pixel is the highest
 point.
 If 
\begin_inset Quotes eld
\end_inset 

yes
\begin_inset Quotes erd
\end_inset 

, the black pixel is the highest point and the white pixel is the lowest
 point.
\layout Subsection

Normalize Image
\layout Standard

If 
\begin_inset Quotes eld
\end_inset 

yes
\begin_inset Quotes erd
\end_inset 

, the darkest pixel is remapped to black, the lightest pixel is remapped
 to white.
\layout Subsection

Expand Image Border
\layout Standard

If 
\begin_inset Quotes eld
\end_inset 

None
\begin_inset Quotes erd
\end_inset 

, the input image is used as-is, and details which are at the very edges
 of the image may be cut off.
 If 
\begin_inset Quotes eld
\end_inset 

White
\begin_inset Quotes erd
\end_inset 

 or 
\begin_inset Quotes eld
\end_inset 

Black
\begin_inset Quotes erd
\end_inset 

, then a border of pixels equal to the tool diameter is added on all sides,
 and details which are at the very edges of the images will not be cut off.
\layout Subsection

Tolerance (units)
\layout Standard

When a series of points are within 
\series bold 
tolerance
\series default 
 of being a straight line, they are output as a straight line.
 Increasing tolerance can lead to better contouring performance in emc,
 but can also remove or blur small details in the image.
\layout Subsection

Pixel Size (units)
\layout Standard

One pixel in the input image will be this many units--usually this number
 is much smaller than 1.0.
 For instance, to mill a 2.5x2.5-inch object from a 400x400 image file, use
 a pixel size of .00625, because 2.5 / 400 = .00625.
\layout Subsection

Plunge Feed Rate (units per minute)
\layout Standard

The feed rate for the initial plunge movement
\layout Subsection

Feed Rate (units per minute)
\layout Standard

The feed rate for other parts of the path
\layout Subsection

Spindle Speed (RPM)
\layout Subsection

Scan Pattern
\layout Standard

Possible scan patterns are:
\layout Itemize

Rows
\layout Itemize

Columns
\layout Itemize

Rows, then Columns
\layout Itemize

Columns, then Rows
\layout Subsection

Scan Direction
\layout Standard

Possible scan directions are:
\layout Itemize

Positive: Start milling at a low X or Y axis value, and move towards a high
 X or Y axis value
\layout Itemize

Negative: Start milling at a high X or Y axis value, and move towards a
 low X or Y axis value
\layout Itemize

Alternating: Start on the same end of the X or Y axis travel that the last
 move ended on.
 This reduces the amount of traverse movements
\layout Itemize

Up Milling: Start milling at low points, moving towards high points
\layout Itemize

Down Milling: Start milling at high points, moving towards low points
\layout Subsection

Depth (units)
\layout Standard

The top of material is always at 
\series bold 
Z=0
\series default 
.
 The deepest cut into the material is 
\series bold 
Z=-depth.
\layout Subsection

Step Over (pixels)
\layout Standard

The distance between adjacent rows or columns.
 To find the number of pixels for a given units distance, compute 
\series bold 
distance/pixel size
\series default 
 and round to the nearest whole number
\series bold 
\emph on 
.
 
\series default 
\emph default 
For example, if 
\series bold 
pixel size=.006 
\series default 
and the desired step over 
\series bold 
distance=.015
\series default 
, then use a Step Over of 2 or 3 pixels, because 
\series bold 
.015/.006=2.5
\emph on 
.
\layout Subsection

Tool Diameter
\layout Standard

The diameter of the cutting part of the tool.
\layout Subsection

Safety Height
\layout Standard

The height to move to for traverse movements.
 image-to-gcode always assumes the top of material is at 
\series bold 
Z=0
\series default 
.
\layout Subsection

Tool Type
\layout Standard

The shape of the cutting part of the tool.
 Possible tool shapes are:
\layout Itemize

Ball End
\layout Itemize

Flat End
\layout Itemize

45 degree 
\begin_inset Quotes eld
\end_inset 

vee
\begin_inset Quotes erd
\end_inset 


\layout Itemize

60 degree 
\begin_inset Quotes eld
\end_inset 

vee
\begin_inset Quotes erd
\end_inset 


\layout Subsection

Lace bounding
\layout Standard

This controls whether areas that are relatively flat along a row or column
 are skipped.
 This option only makes sense when both rows and columns are being milled.
 Possible bounding options are:
\layout Itemize

None: Rows and columns are both fully milled.
\layout Itemize

Secondary: When milling in the second direction, areas that do not strongly
 slope in that direction are skipped.
\layout Itemize

Full: When milling in the first direction, areas that strongly slope in
 the second direction are skipped.
 When milling in the second direction, areas that do not strongly slope
 in that direction are skipped.
\layout Subsection

Contact angle
\layout Standard

When 
\series bold 
Lace bounding
\series default 
 is not None, slopes greater than 
\series bold 
Contact angle
\series default 
 are considered to be 
\begin_inset Quotes eld
\end_inset 

strong
\begin_inset Quotes erd
\end_inset 

 slopes, and slopes less than that angle are considered to be weak slopes.
\layout Subsection

Roughing offset and depth per pass
\layout Standard

Image-to-gcode can optionally perform rouging passes.
 The depth of successive roughing passes is given by 
\begin_inset Quotes eld
\end_inset 

Roughing depth per pass
\begin_inset Quotes erd
\end_inset 

.
 For instance, entering 0.2 will perform the first roughing pass with a depth
 of 0.2, the second roughing pass with a depth of 0.4, and so on until the
 full Depth of the image is reached.
 No part of any roughing pass will cut closer than Roughing Offset to the
 final part.
 Figure 
\begin_inset LatexCommand \ref{cap:Roughing-passes-and}

\end_inset 

 shows a tall vertical feature being milled.
 In this image, Roughing depth per pass is 0.2 inches and roughing offset
 is 0.1 inches.
\layout Standard


\begin_inset Float figure
wide false
collapsed false

\layout Caption

Roughing passes and final pass
\begin_inset LatexCommand \label{cap:Roughing-passes-and}

\end_inset 


\layout Standard
\align center 

\begin_inset Graphics
	filename i2g-roughing.png

\end_inset 


\end_inset 


\the_end