STL to SCAD - Revision history

Ubuntourist: Explicitly mention a difference() shape

2017-08-18T21:50:35Z

Explicitly mention a difference() shape

← Older revision		Revision as of 21:50, 18 August 2017
Line 22:		Line 22:
	linear_extrude(height=10)		linear_extrude(height=10)
	import("bottom.dxf");		import("bottom.dxf");
	* Since the object in question changes shape at different "heights" several layers need to be cut away in order to get a newer shape. In OpenSCAD this is done by creating another shape and subtracting it from the initial shape with a difference() operation.		* Since the object in question changes shape at different "heights" several layers need to be cut away in order to get a newer shape. In OpenSCAD this is done by creating another shape and subtracting it from the initial shape with a difference() operation. I leave it as an exercise for the reader to choose a reasonable cut-away. (I think I used a 160 x 160 x 10 cube translated to encompass the entire bottom of the object.)
	* Unfortunately, operations on STL files can go wrong because STL files are often produced sloppily. Fortunately [https://www.freecadweb.org/ FreeCAD] is one of the programs that can repair STL files. See [http://manual.slic3r.org/advanced/repairing-models Sli3r's page on repairing models] for instructions. (The STL file used in this document had to be iteratively repaired multiple times before FreeCAD reported no errors.		* Unfortunately, operations like '''difference()''' on STL files can go wrong because STL files are often produced sloppily. Fortunately [https://www.freecadweb.org/ FreeCAD] is one of the programs that can repair STL files. See [http://manual.slic3r.org/advanced/repairing-models Sli3r's page on repairing models] for instructions. (The STL file used in this document had to be iteratively repaired multiple times before FreeCAD reported no errors.
	* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG (word-wrapped from the original, for your pleasure):		* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG (word-wrapped from the original, for your pleasure):
	<svg width="108" height="96"		<svg width="108" height="96"

Ubuntourist: Final? version

2017-08-18T15:51:24Z

Final? version

← Older revision		Revision as of 15:51, 18 August 2017
Line 1:		Line 1:
			==== Written by Ubuntourist (Kevin Cole) 2017.08.18 ====
	Suppose you have an STL for a part to be 3D printed. In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/		Suppose you have an STL for a part to be 3D printed. In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/

	[[File:Assembly_v4_rev3.png\|frameless]] (Click the image for a larger view. For the full 360, watch the '''[[:media:bowden.ogv\|movie]]'''.)		[[File:Assembly_v4_rev3.png\|frameless]] (Click the image for a larger view. For the full 360, watch the '''[[:media:bowden.ogv\|movie]]'''.)

	Sadly, these are impossible to work with.		Sadly, these are impossible to work with. At least, with Free / Libre Open Source Software (FLOSS).
			== Prerequisites ==
			You should be able to repeat the whole process below and beta-test my documentation. The prerequisites are:
			* the Thingiverse STL file,
			* [http://www.openscad.org/ OpenSCAD] (I don't know how well [http://implicitcad.org ImplicitCAD] handles the importing and exporting needed, but it's well worth exploring.),
			* [https://www.freecadweb.org/ FreeCAD],
			* a basic familiarity with primitive shapes, transformations, differences and unions in OpenSCAD. If those mean nothing to you, get thee hie to the [http://www.openscad.org/documentation.html OpenSCAD manual] and read up.
			* and, of course, the One True Editor. ;-) Actually, I may write a Python program to automate the editing.
	== Stupid pet tricks with OpenSCAD ==		== Stupid pet tricks with OpenSCAD ==
			* These next three lines import and flatten the STL. The result can be exported as SVG, DFX, or any of several other formats. I saved the result as both '''bottom.svg''' and '''bottom.dfx'''.
	The prerequisite here is that you're already somewhat familiar with basic shapes, transformations, differences and unions. If not, get thee hie to the [http://www.openscad.org/documentation.html OpenSCAD manual] and read up.

	* These next three lines import and flatten the STL. The result can be exported as SVG, DFX, or several other formats. I saved it as both bottom.svg and bottom.dfx.

	projection() // Flatten		projection() // Flatten
	translate([0, 0, -10]) // The original STL appeared "hover" mid-air. This brought it back to earth.		translate([0, 0, -10]) // The original STL appeared "hover" mid-air. This brought it back to earth.
	import("assembly_v4_rev3.stl"); // STL unzipped from the Thingiverse download.		import("assembly_v4_rev3.stl"); // STL unzipped from the Thingiverse download.

	:resulting in:		:resulting in:
	[[File:Bottom.svg\|frameless]] (Note: This is an SVG rather than a DFX, but the concept / result is nearly the same.)		[[File:Bottom.svg\|frameless]] (Note: This is an SVG rather than a DFX, but the concept / result is nearly the same.)
	* The DFX (at least) can be read in again and extruded:		* The DFX (at least) can be read in again and extruded:

	linear_extrude(height=10)		linear_extrude(height=10)
	import("bottom.dxf");		import("bottom.dxf");
	* Since the object in question changes shape at different "heights" several layers need to be cut away in order to get a newer shape. In OpenSCAD this is done by creating another shape and subtracting it from the initial shape with a difference() operation.		* Since the object in question changes shape at different "heights" several layers need to be cut away in order to get a newer shape. In OpenSCAD this is done by creating another shape and subtracting it from the initial shape with a difference() operation.
	* Unfortunately, operations on STL files can go wrong because STL files are often produced sloppily. Fortunately [https://www.freecadweb.org/ FreeCAD] is one of the programs that can repair STL files. See [http://manual.slic3r.org/advanced/repairing-models Sli3r's page on repairing models] for instructions. (The STL file used in this document had to be iteratively repaired multiple times before FreeCAD reported no errors.		* Unfortunately, operations on STL files can go wrong because STL files are often produced sloppily. Fortunately [https://www.freecadweb.org/ FreeCAD] is one of the programs that can repair STL files. See [http://manual.slic3r.org/advanced/repairing-models Sli3r's page on repairing models] for instructions. (The STL file used in this document had to be iteratively repaired multiple times before FreeCAD reported no errors.
	* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG:		* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG (word-wrapped from the original, for your pleasure):

	<svg width="108" height="96"		<svg width="108" height="96"
	viewBox="-62 -50 108 96"		viewBox="-62 -50 108 96"
Line 34:		Line 35:
	stroke="black" fill="lightgray" stroke-width="0.5">		stroke="black" fill="lightgray" stroke-width="0.5">
	</svg>		</svg>

	* OpenSCAD polygon definitions are lists of points enclosed in brackets [point, point, point, ..., point]. Each point is an X, Y coordinate pair, also enclosed in brackets [X,Y]. So, the full shape looks like [[X,Y], [X,Y], [X,Y], ..., [X, Y]].		* OpenSCAD polygon definitions are lists of points enclosed in brackets [point, point, point, ..., point]. Each point is an X, Y coordinate pair, also enclosed in brackets [X,Y]. So, the full shape looks like [[X,Y], [X,Y], [X,Y], ..., [X, Y]].
	* Edit the SVG with the following rules:		* Edit the SVG with the following rules:
Line 43:		Line 43:
	** '''z''' finishes off the current polygon. Convert each to ''']);'''		** '''z''' finishes off the current polygon. Convert each to ''']);'''
	* The result should be:		* The result should be:

	polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);		polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);
	polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);		polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);
	...		...
	polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);		polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);

	* I suspect, in general, the first polygon will be the general outline, and the subsequent polygons will be "holes" in the shape. So, surround the whole thing with a '''difference()''' and add a linear_extrude() to get some height:		* I suspect, in general, the first polygon will be the general outline, and the subsequent polygons will be "holes" in the shape. So, surround the whole thing with a '''difference()''' and add a linear_extrude() to get some height:

	linear_extrude(height=10) { // e.g. 10mm high		linear_extrude(height=10) { // e.g. 10mm high
	difference() {		difference() {
Line 59:		Line 56:
	}		}
	}		}

	* Voila! Done! You now have a parametric representation, albeit an ugly, incomplete one, of what was once an STL file.		* Voila! Done! You now have a parametric representation, albeit an ugly, incomplete one, of what was once an STL file.

Ubuntourist: Link to OpenSCAD manual. Formatting clean-up.

2017-08-18T15:30:32Z

Link to OpenSCAD manual. Formatting clean-up.

← Older revision		Revision as of 15:30, 18 August 2017
Line 5:		Line 5:
	Sadly, these are impossible to work with.		Sadly, these are impossible to work with.
	== Stupid pet tricks with OpenSCAD ==		== Stupid pet tricks with OpenSCAD ==

			The prerequisite here is that you're already somewhat familiar with basic shapes, transformations, differences and unions. If not, get thee hie to the [http://www.openscad.org/documentation.html OpenSCAD manual] and read up.

	* These next three lines import and flatten the STL. The result can be exported as SVG, DFX, or several other formats. I saved it as both bottom.svg and bottom.dfx.		* These next three lines import and flatten the STL. The result can be exported as SVG, DFX, or several other formats. I saved it as both bottom.svg and bottom.dfx.

	projection()		projection() // Flatten
	translate([0, 0, -10]) // The original appeared "hover" mid-air.		translate([0, 0, -10]) // The original STL appeared "hover" mid-air. This brought it back to earth.
	import("assembly_v4_rev3.stl");		import("assembly_v4_rev3.stl"); // STL unzipped from the Thingiverse download.

	:resulting in:		:resulting in:
Line 22:		Line 24:
	* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG:		* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG:

	<svg width="108" height="96"		<svg width="108" height="96"
	viewBox="-62 -50 108 96"		viewBox="-62 -50 108 96"
	xmlns="http://www.w3.org/2000/svg"		xmlns="http://www.w3.org/2000/svg"
	version="1.1">		version="1.1">
	<path d="M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z		<path d="M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z
	M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z		M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z
	...		...
	M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z"		M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z"
	stroke="black" fill="lightgray" stroke-width="0.5">		stroke="black" fill="lightgray" stroke-width="0.5">
	</svg>		</svg>

	* OpenSCAD polygon definitions are lists of points enclosed in brackets [point, point, point, ..., point]. Each point is an X, Y coordinate pair, also enclosed in brackets [X,Y]. So, the full shape looks like [[X,Y], [X,Y], [X,Y], ..., [X, Y]].		* OpenSCAD polygon definitions are lists of points enclosed in brackets [point, point, point, ..., point]. Each point is an X, Y coordinate pair, also enclosed in brackets [X,Y]. So, the full shape looks like [[X,Y], [X,Y], [X,Y], ..., [X, Y]].
Line 42:		Line 44:
	* The result should be:		* The result should be:

			polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);
			polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);
			...
			polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);

			* I suspect, in general, the first polygon will be the general outline, and the subsequent polygons will be "holes" in the shape. So, surround the whole thing with a '''difference()''' and add a linear_extrude() to get some height:

			linear_extrude(height=10) { // e.g. 10mm high
			difference() {
	polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);		polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);
	polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);		polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);
			...
	polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);		polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);
			}
	* I suspect, in general, the first polygon will be the general outline, and the subsequent polygons will be "holes" in the shape. So, surround the whole thing with a '''difference()''' and add a linear_extrude() to get some height:		}

	~~linear_extrude(height=10) { // e.g. 10mm high~~
	~~difference() {~~
	~~polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);~~
	~~polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);~~
	~~polygon([[x1, y1], [x2, y2], [x3, y3], ... [xN, yN]]);~~
	}

	* Voila! Done! You now have a parametric representation, albeit an ugly, incomplete one, of what was once an STL file.		* Voila! Done! You now have a parametric representation, albeit an ugly, incomplete one, of what was once an STL file.

Ubuntourist: Signature and more detail

2017-08-18T15:20:13Z

Signature and more detail

← Older revision		Revision as of 15:20, 18 August 2017
Line 4:		Line 4:

	Sadly, these are impossible to work with.		Sadly, these are impossible to work with.


	== Stupid pet tricks with OpenSCAD ==		== Stupid pet tricks with OpenSCAD ==

Line 24:		Line 22:
	* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG:		* Although extruding imported DXF files works after a fashion, it's still not really editable source code. It ain't pretty, but there's a fix for that as well. The SVG produced from the '''projection()''' and export is a series of polygons, each of which is a series of point coordinates. Look at the '''path''' element of the SVG:

			<svg width="108" height="96"
			viewBox="-62 -50 108 96"
			xmlns="http://www.w3.org/2000/svg"
			version="1.1">
	<path d="M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z		<path d="M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z
	M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z		M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z
			...
	M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z"		M x1,y1 L x2,y2 L x3,y3 ... L xN,yN z"
			stroke="black" fill="lightgray" stroke-width="0.5">
			</svg>

	* OpenSCAD polygon definitions are lists of points enclosed in brackets [point, point, point, ..., point]. Each point is an X, Y coordinate pair, also enclosed in brackets [X,Y]. So, the full shape looks like [[X,Y], [X,Y], [X,Y], ..., [X, Y]].		* OpenSCAD polygon definitions are lists of points enclosed in brackets [point, point, point, ..., point]. Each point is an X, Y coordinate pair, also enclosed in brackets [X,Y]. So, the full shape looks like [[X,Y], [X,Y], [X,Y], ..., [X, Y]].
	* Edit the SVG with the following rules:		* Edit the SVG with the following rules:
	** The opening and closing '''svg''' tags at the beginning and end of the file should be removed as should the '''stroke="black" fill="lightgray" stroke-width="0.5"''' attributes at the end of the '''path''' element. Really, everything except the contents of the '''d''' attribute of the '''path''' element should be stripped away -- although the '''viewbox''', '''height''' and '''width''' attributes in the initial opening '''svg''' tag may offer further clues at a later date.		** The opening and closing '''svg''' tags at the beginning and end of the file should be removed as should the '''stroke="black" fill="lightgray" stroke-width="0.5"''' attributes at the end of the '''path''' element. Really, everything except the contents of the '''d''' attribute of the '''path''' element should be stripped away -- although the '''viewbox''', '''height''' and '''width''' attributes in the initial opening '''svg''' tag may offer further clues at a later date.
	** '''M''' ~~is a~~ '''move to''' (pen up) command and marks the start of a '''polygon'''. Convert it to '''polygon(['''		** '''M''' are '''move to''' (pen up) command and marks the start of a '''polygon'''. Convert them to '''polygon(['''
	** '''L''' ~~is a~~ '''line to''' (pen down) command. Eliminate it.		** '''L''' are '''line to''' (pen down) command. Eliminate them -- but not the coordinate pairs that follow each of them.
	** number pairs are X and Y coordinates and should be enclosed in brackets and all but the last should be followed by a comma. '''[X,Y], '''		** number pairs are X and Y coordinates and should be enclosed in brackets and all but the last should be followed by a comma. '''[X,Y], '''
	** '''z''' finishes off the current polygon. Convert it to ''']);'''		** '''z''' finishes off the current polygon. Convert each to ''']);'''
	* The result should be:		* The result should be:

Line 57:		Line 62:

	[[File:Fullish.png\|frameless]]		[[File:Fullish.png\|frameless]]

			----
			--[[User:Ubuntourist\|Ubuntourist]] ([[User talk:Ubuntourist\|talk]]) 08:20, 18 August 2017 (PDT)

Ubuntourist: Added final results attachments

2017-08-18T15:05:59Z

Added final results attachments

← Older revision		Revision as of 15:05, 18 August 2017
Line 1:		Line 1:
	Suppose you have an STL for a part to be 3D printed. In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/		Suppose you have an STL for a part to be 3D printed. In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/

	[[File:Assembly_v4_rev3.png\|frameless]] (Click the image for a larger view. For the full 360, watch the '''[[:media:bowden.ogv\|movie]]'''.)		[[File:Assembly_v4_rev3.png\|frameless]] (Click the image for a larger view. For the full 360, watch the '''[[:media:bowden.ogv\|movie]]'''.)

	Sadly, these are impossible to work with.		Sadly, these are impossible to work with.

Line 49:		Line 51:

	* Voila! Done! You now have a parametric representation, albeit an ugly, incomplete one, of what was once an STL file.		* Voila! Done! You now have a parametric representation, albeit an ugly, incomplete one, of what was once an STL file.
	* There's still a LOT of work to be done for holes that are not completely vertical. Completely horizontal holes are gonna be a BITCH! In fact any odd changes in the Z direction will be trouble. Some of that trouble can be solved by more difference() stanzas in the original STL, while others may be ferreted out by 90° and 180° rotations along various axis, possibly combined with difference().
			There's still a LOT of work to be done for holes that are not completely vertical. Completely horizontal holes are gonna be a BITCH! In fact any odd changes in the Z direction will be trouble. Some of that trouble can be solved by more difference() stanzas in the original STL, while others may be ferreted out by 90° and 180° rotations along various axis, possibly combined with difference().

			The end result, produced by '''[[:File:Fullish.scad\|fullish.scad]]''' (the combination of bottom.scad and top.scad):

			[[File:Fullish.png\|frameless]]

Ubuntourist: A rough draft

2017-08-18T14:53:38Z

A rough draft

@@ Line 1: / Line 1: @@
 Suppose you have an STL for a part to be 3D printed.  In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/
-[[File:Assembly_v4_rev3.png|frameless]] (Click the image for a larger view. For a full 360 view of the part, see the '''[[:media:bowden.ogv|movie]]'''.)
+[[File:Assembly_v4_rev3.png|frameless]] (Click the image for a larger view. For the full 360, watch the '''[[:media:bowden.ogv|movie]]'''.)
 Sadly, these are impossible to work with.
-Stupid pet tricks with OpenSCAD:
 * These next three lines import and flatten the STL.  The result can be exported as SVG, DFX, or several other formats. I saved it as both bottom.svg and bottom.dfx.
@@ Line 12: / Line 13: @@
 :resulting in:
+[[File:Bottom.svg|frameless]] (Note: This is an SVG rather than a DFX, but the concept / result is nearly the same.)
 * The DFX (at least) can be read in again and extruded:
      linear_extrude(height=10)
        import("bottom.dxf");

Ubuntourist: WIP

2017-08-18T01:41:58Z

WIP

← Older revision		Revision as of 01:41, 18 August 2017
Line 1:		Line 1:
	Suppose you have an STL for a part to be 3D printed. In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/		Suppose you have an STL for a part to be 3D printed. In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/
			[[File:Assembly_v4_rev3.png\|frameless]] (Click the image for a larger view. For a full 360 view of the part, see the '''[[:media:bowden.ogv\|movie]]'''.)
			Sadly, these are impossible to work with.

	[[:~~media~~:~~bowden~~.~~ogv\|movie]]~~		Stupid pet tricks with OpenSCAD:

			* These next three lines import and flatten the STL. The result can be exported as SVG, DFX, or several other formats. I saved it as both bottom.svg and bottom.dfx.

			projection()
			translate([0, 0, -10]) // The original appeared "hover" mid-air.
			import("assembly_v4_rev3.stl");

			:resulting in:

			* The DFX (at least) can be read in again and extruded:

			linear_extrude(height=10)
			import("bottom.dxf");

Ubuntourist: WIP

2017-08-18T01:26:44Z

WIP

← Older revision		Revision as of 01:26, 18 August 2017
Line 1:		Line 1:
	[[~~File~~:bowden.ogv]] ~~to use the full version of the file~~		Suppose you have an STL for a part to be 3D printed. In this case, an '''HST double bolt bowden extruder V4 assembly''' downloaded from: https://www.thingiverse.com/thing:515747/

			[[:media:bowden.ogv\|movie]]

Ubuntourist: Initial commit

2017-08-18T01:17:23Z

Initial commit

New page

[[File:bowden.ogv]] to use the full version of the file