Spacing Next we must consider the spacing of the images. The 3D effect relies heavily on geometry, so we have to make some assumptions about how the images will be viewed. The majority of people who see 3D Ascii artwork will be using an 80 column display, on a screen about 12 - 14 inches wide and sitting about 3 or 4 feet away from it. 3D Printing Keys – images into 3D models. Right so lets get to it. For the main tutorial I will be showing how to convert a 2D drawing into a coffee art stencil. A coffee art stencil is a stencil used to sprinkle chocolate or other powder onto top of coffee in shapes. The two formats contain the same information about the model, but the binary format is much more compact, so it will produce smaller files from the same part but they should work the same.That's to say, if you take the exact same model, save it as a binary STL and as an ASCII STL, the binary STL file will take up fewer bytes on disk. The number of triangles and the dimensions of the printed. Cults is for you! Browse our different categories and download the best 3D printer models for free, open-source or paid mode, in.STL,.OBJ or.SCAD format, they are all 3D printable guaranteed. We are connecting 3D print files makers with people who want to use their 3D printer. Our 3D model repository acts as a real source of inspiration.
STL
A CAD representation of a torus (shown as two concentric red circles) and an STL approximation of the same shape (composed of triangular planes)
Filename extension
Internet media type
Developed by3D Systems
Initial release1987
Type of formatStereolithography
STL is a file format native to the stereolithographyCAD software created by 3D Systems.[1][2][3] STL has several backronyms such as 'Standard Triangle Language' and 'Standard Tessellation Language'.[4] This file format is supported by many other software packages; it is widely used for rapid prototyping, 3D printing and computer-aided manufacturing.[5] Rottenwood. STL files describe only the surface geometry of a three-dimensional object without any representation of color, texture or other common CAD model attributes. The STL format specifies both ASCII and binary representations. Binary files are more common, since they are more compact.[6]
An STL file describes a raw, unstructured triangulated surface by the unitnormal and vertices (ordered by the right-hand rule) of the triangles using a three-dimensional Cartesian coordinate system. In the original specification, all STL coordinates were required to be positive numbers, but this restriction is no longer enforced and negative coordinates are commonly encountered in STL files today. STL files contain no scale information, and the units are arbitrary.[7]
Ascii

ASCII STL[edit]

An ASCII STL file begins with the line
where name is an optional string (though if name is omitted there must still be a space after solid). The file continues with any number of triangles, each represented as follows:
where each n or v is a floating-point number in sign-mantissa-'e'-sign-exponent format, e.g., '2.648000e-002'. The file concludes with
An example ASCII STL of a sphericon
The structure of the format suggests that other possibilities exist (e.g., facets with more than one 'loop', or loops with more than three vertices). Indivisible 1 0 38929 – an action rpg platformer game. In practice, however, all facets are simple triangles.
White space (spaces, tabs, newlines) may be used anywhere in the file except within numbers or words. The spaces between 'facet' and 'normal' and between 'outer' and 'loop' are required.[6]

Binary STL[edit]

Because ASCII STL files can become very large, a binary version of STL exists. A binary STL file has an 80-character header (which is generally ignored, but should never begin with 'solid' because that may lead some software to assume that this is an ASCII STL file). Following the header is a 4-byte little-endian unsigned integer indicating the number of triangular facets in the file. Following that is data describing each triangle in turn. The file simply ends after the last triangle.
Each triangle is described by twelve 32-bit floating-point numbers: three for the normal and then three for the X/Y/Z coordinate of each vertex – just as with the ASCII version of STL. After these follows a 2-byte ('short') unsigned integer that is the 'attribute byte count' – in the standard format, this should be zero because most software does not understand anything else.[6]
Floating-point numbers are represented as IEEE floating-point numbers and are assumed to be little-endian, although this is not stated in documentation.

Color in binary STL[edit]

There are at least two non-standard variations on the binary STL format for adding color information:
  • The VisCAM and SolidView software packages use the two 'attribute byte count' bytes at the end of every triangle to store a 15-bit RGB color:
    • bits 0 to 4 are the intensity level for blue (0 to 31),
    • bits 5 to 9 are the intensity level for green (0 to 31),
    • bits 10 to 14 are the intensity level for red (0 to 31),
    • bit 15 is 1 if the color is valid, or 0 if the color is not valid (as with normal STL files).
  • The Materialise Magics software uses the 80-byte header at the top of the file to represent the overall color of the entire part. If color is used, then somewhere in the header should be the ASCII string 'COLOR=' followed by four bytes representing red, green, blue and alpha channel (transparency) in the range 0–255. This is the color of the entire object, unless overridden at each facet. Magics also recognizes a material description; a more detailed surface characteristic. Just after 'COLOR=RGBA' specification should be another ASCII string ',MATERIAL=' followed by three colors (3×4 bytes): first is a color of diffuse reflection, second is a color of specular highlight, and third is an ambient light. Material settings are preferred over color. The per-facet color is represented in the two 'attribute byte count' bytes as follows:
    • bits 0 to 4 are the intensity level for red (0 to 31),
    • bits 5 to 9 are the intensity level for green (0 to 31),
    • bits 10 to 14 are the intensity level for blue (0 to 31),
    • bit 15 is 0 if this facet has its own unique color, or 1 if the per-object color is to be used.
The red/green/blue ordering within those two bytes is reversed in these two approaches – so while these formats could easily have been compatible, the reversal of the order of the colors means that they are not – and worse still, a generic STL file reader cannot automatically distinguish between them. Valentina studio pro keygen. There is also no way to have facets be selectively transparent because there is no per-facet alpha value – although in the context of current rapid prototyping machinery, this is not important.

The facet normal[edit]

In both ASCII and binary versions of STL, the facet normal should be a unit vector pointing outwards from the solid object. In most software this may be set to (0,0,0), and the software will automatically calculate a normal based on the order of the triangle vertices using the 'right-hand rule'. Some STL loaders (e.g. the STL plugin for Art of Illusion) check that the normal in the file agrees with the normal they calculate using the right-hand rule and warn the user when it does not. Other software may ignore the facet normal entirely and use only the right-hand rule. Although it is rare to specify a normal that cannot be calculated using the right-hand rule, in order to be entirely portable, a file should both provide the facet normal and order the vertices appropriately.A notable exception is SolidWorks, which uses the normal for shading effects.

Use in 3D printing[edit]

3D printers build objects by solidifying one layer at a time. This requires a series of closed 2D contours that are filled in with solidified material as the layers are fused together. A natural file format for such a machine would be a series of closed polygons corresponding to different Z-values. However, since it is possible to vary the layer thicknesses for a faster though less precise build, it was easier to define the model to be built as a closed polyhedron that can be sliced at the necessary horizontal levels.
The STL file format appears capable of defining a polyhedron with any polygonal facet, but in practice it is only ever used for triangles, which means that much of the syntax of the ASCII protocol is superfluous.
To properly form a 3D volume, the surface represented by any STL files must be closed and connected, where every edge is part of exactly two triangles, and not self-intersecting. Since the STL syntax does not enforce this property, it can be ignored for applications where the closedness does not matter. The closedness only matters insofar as the software that slices the triangles requires it to ensure that the resulting 2D polygons are closed. Sometimes such software can be written to clean up small discrepancies by moving vertices that are close together so that they coincide. The results are not predictable, but it is often sufficient.

Use in other fields[edit]

STL model of the Utah teapot viewed in the MediaWiki 3D extension
STL file format is simple and easy to output. Consequently, many computer-aided design systems can output the STL file format. Although the output is simple to produce, some connectivity information is discarded.
Many computer-aided manufacturing systems require triangulated models. STL format is not the most memory- and computationally efficient method for transferring this data, but STL is often used to import the triangulated geometry into the CAM system. The format is commonly available, so the CAM system will use it. In order to use the data, the CAM system may have to reconstruct the connectivity. As STL files do not save the physical dimension of a unit, a CAM system will ask for it. Typical units are mm and inch.
STL can also be used for interchanging data between CAD/CAM systems and computational environments such as Mathematica.

Representation of curved surfaces[edit]

It is not possible to use triangles to perfectly represent curved surfaces. To compensate, users often save enormous STL files to reduce the inaccuracy. Native formats of 3D design software files use mathematical surfaces to preserve detail losslessly in small files.

History[edit]

STL was invented by the Albert Consulting Group for 3D Systems in 1987.[8] The format was developed for 3D Systems' first commercial 3D printers. Since its initial release, the format remained relatively unchanged for 22 years. In 2009, an update to the format, dubbed STL 2.0, was proposed.[9][10]

See also[edit]

  • 3D Manufacturing Format (3MF), a standard for 3D file manufacturing
  • Additive Manufacturing File Format (AMF), a standard with support for color, multiple materials, and constellations
  • PLY (file format), an alternative file format
  • Wavefront .obj file, a 3D geometry definition file format with .obj file extension
  • X3D, a royalty-free ISO standard for 3D computer graphics

References[edit]

  1. ^StereoLithography Interface Specification, 3D Systems, Inc., July 1988
  2. ^StereoLithography Interface Specification, 3D Systems, Inc., October 1989
  3. ^SLC File Specification, 3D Systems, Inc., 1994
  4. ^Grimm, Todd (2004), User's Guide to Rapid Prototyping, Society of Manufacturing Engineers, p. 55, ISBN0-87263-697-6. Many names are used for the format: for example, 'standard triangle language', 'stereolithography language', and 'stereolithography tesselation language'. Page 55 states, 'Chuck Hull, the inventor of stereolithography and 3D Systems' founder, reports that the file extension is for stereolithography.'
  5. ^Chua, C. K; Leong, K. F.; Lim, C. S. (2003), Rapid Prototyping: Principles and Applications (2nd ed.), World Scientific Publishing Co, ISBN981-238-117-1 Chapter 6, Rapid Prototyping Formats. Page 237, 'The STL (STeroLithography) file, as the de facto standard, has been used in many, if not all, rapid prototyping systems.' Section 6.2 STL File Problems. Section 6.4 STL File Repair.
  6. ^ abcBurns, Marshall (1993). Automated Fabrication. Prentice Hall. ISBN978-0-13-119462-5.
  7. ^fabbers.com Historical resource on 3D printing, The StL Format: Standard Data Format for Fabbers, reprinted from Marshall Burns, Automated Fabrication, http://www.ennex.com/~fabbers/StL.asp stating, 'The object represented must be located in the all-positive octant. In other words, all vertex coordinates must be positive-definite (nonnegative and nonzero) numbers. The StL file does not contain any scale information; the coordinates are in arbitrary units.'
  8. ^'STL File Format for 3D Printing - Explained in Simple Terms'. All3DP. 17 November 2016. Retrieved 5 May 2017.
  9. ^'STL 2.0 May Replace Old, Limited File Format'. RapidToday. Retrieved 5 May 2017.
  10. ^Hiller, Jonathan D.; Lipson, Hod (2009). 'STL 2.0: A Proposal for a Universal Multi-Material Additive Manufacturing File Format'(PDF). Cornell University. Retrieved 5 May 2017.

External links[edit]

  • The STL Format - Standard Data Format for Fabbers
Retrieved from 'https://en.wikipedia.org/w/index.php?title=STL_(file_format)&oldid=978446766'

3d Images For 3d Printer

H. G. Dietz
http://aggregate.org/hankd/

Department of Electrical and Computer Engineering
Center for Visualization & Virtual Environments
University of Kentucky, Lexington, KY 40506-0046

Initial release: January 4, 2015; last update: September 19, 2015

This document should be cited using something like the bibtex entry:
Anyone who has ever played with a 3D printer no doubt almostimmediately encountered the little problem of having a 2D imagethat they wanted to convert into a 3D model. However, there's aspecial reason this became a priority for me now: for the firsttime in over three decades of being a professor, in Fall 2015, Iwill have a blind student in one of the classes I teach. Mycourse unfortunately has significant visual components in theform of various diagrams, so one of the obvious possibleapproaches would be to try to use my 3D printer to createtactile versions of the key graphics for the course. I createdtrace2scad to facilitate making these 'bump readable'graphic images using my MakerGear M2 3D printer.
Trace2SCAD is distributed as full sourcecode under Creative Commons - Attribution constraints. Youuse it at your own risk, with no warranty, etc.

3d Printer Images Sample

Background

There are many ways to convert 2D graphics into a 3D-printablemodel. There are even a number of free software toolsexplicitly supporting this type of transformation. To name afew:
  • PNG23D is avery widely available free tool that converts a PNG image intoeither an OpenSCAD or STL file. It's not fast, but directlygenerates a triangle mesh for a manifold polygon representingthe pixel values as heights. Put another way, this converts animage into a Lithophane, and can even deal with color.
  • Img2SCAD is aPython tool that converts a monochrome image into an OpenSCADstructure that is essentially a cube per pixel, such that thecube height represents the 'whiteness' of the correspondingpixel.
  • OpenSCAD itself has long included a surface()primitive that can read a raw data file and represent it an anobject where the height at each point corresponds to the datavalue for that point, with nicely sloped transitions betweenpoints. The data file format is not an image per se, butconsists of ASCII text giving whitespace-separated integer pixelheights -- which is easily generated by stripping the header offan ASCII PGM file (the type that begins with the sequenceP2). As of the 2014.QX versions, there is also provisionfor reading-in a PNG image, with gray scale values computedas Y = 0.2126R + 0.7152G + 0.0722B and scaled to 0.100.
  • Inkscape offers a verydifferent alternative. It is capable of directly manipulatingvector drawings and can even trace pixel-based images to createvector forms. These vetor forms can then be saved as DXF files,which tools like OpenSCAD can import directly. The catch is thatthe vector model in Inkscape is far more general than what DXFfiles can represent, so the drawing must be processed to removeconstructs like smooth curves, replacing them all withstraight-line segments. In the 'Extensions' menu, there is anoption called 'Flatten Beziers' which does this simplificationwith a user-settable 'Flatness,' but it is notoriouslyunreliable. It is worth noting that the output of Inkscape iscompletely flat in the sense that model height is fixed at 1unit.
  • Image to lithophaneis a fantastic WWW-based tool for creating 3D STL meshes fromimages. It's probably what you want if you want to makelithophanes. However, it generates models with complexityproportional to image pixel count.
  • Curanow has the ability to read-in an image file and create a smoothedheight-map, which it can 'save model' as an STL file. It's notparticularly clever, but it's free, fast, and really easy to use.Model complexity is proportional to pixel count.Can be used to make simple lithophanes.
  • Selva3D is yet anotherWWW-based tool for generating 3D models from 2D images. Itcharges for 'high quality' STLs, but delivers lower-quality onesfor free after a 2-minute delay. It seems to be attempting tosimplify the model much as trace2scad does, but perhapsnot as successfully. Still, it does appear to generate 3D outputdirectly.

3d Printer Images To Print

Given all those different approaches (and there are many othersnot mentioned above), why are we creating and posting yetanother tool to convert images into models? Well, we generate anOpenSCAD model, not an STL file. In addition, OpenSCADdoesn't deal well with very complex models, so we try tomoderate model complexity. Unfortunately, to get smooth-lookingstructures from all the above except Inkscape, you need lots ofpixels and model complexity for most of the above is directlyproportional to the total number of pixels in the image.Inkscape solves this problem, but not in an easy to use norreliable way. Trace2SCAD is doing much the same processing as wewould do with Inkscape, but it is much faster, easier to use,directly generates an OpenSCAD model of controllable size, andhopefully will prove to be more reliable.
One more thing: trace2scad also knows how to buildmulti-layer models somewhat like the pixel bump maps built byother tools, but not based on pixels. The 3D modelsare presented as a set of discrete layers, so it would be moretechnically correct to call it 2.5D rather than 3D.

Image Ascii 2 3d Printer Installer

How Trace2SCAD Works

Trace2SCAD is a shell script using sed, awk,ImageMagick convert, mkbitmap, andpotrace. Thanks to convert, nearly any imagefile format can be used for the input, and mkbitmap isused to further enhance the image for procesing, but the bulk ofthe work is really done by the incredibly useful Potrace. That toolis also what does the heavy lifting for Inkscape. However,rather than letting potrace go to all the work ofgenerating smooth curves and then converting them tostraight-line segments, we simply tell potrace tooutput straight-line segments. The specific style of grouped SVGoutput by potrace is then parsed and reprocessed tocreate an OpenSCAD module definition.
There are a few options that we'll discuss in the followingsection, but there is one that is particularly important andunique to this tool: trace2scad allows you to specify amaximum model complexity, and will automatically iteratesimplifying the image and retracing until a model is createdthat does not exceed the target complexity. Thus, you havedirect control over the compexity of the OpenSCAD model -- whichis critical given that OpenSCAD can take many hours to renderoverly complex models, often quietly failing after many hours ofprocessing.

Ascii 3d Text

Using Trace2SCAD

Trace2SCAD is really very easy to use, essentially able toaccept just about any type of 2D image file as input anddirectly generating an output file that contains the OpenSCADmodel as a set of module definitions. The modules are alwaysscaled to be bounded within a 1mm cube that is sitting on theZ=0 plane and is centered at X=0, Y=0. That is almost certainlytoo small to be used directly; for example, iflithophane() is the name of a generated module that youwant to make have a maximum X or Y dimension of 100mm and Z 3mm,this can be done using scale([100, 100, 3])lithophane();. Note that the X/Y aspect ratio of theoriginal image is preserved by trace2scad, so the X andY scaling components should normally be the same value.
At this writing, the command line for trace2scad hasfair number of options, but most are rarely needed. The basicusage is:
The command line options are:
-a
Force alignment of the model based on image bounds (also--align). Normally, the model is centered based on thebounding box computed from the generated models, but that meansposition of the object within the original image is lost. Thus,overlaying multiple trace2scad models from the sameoriginal image will not align them. To ensure alignment,-a is automatically set if you are generating modelsfor more than one layer.
-cnumber
Set the target model complexity (also --complex). Themodel will be iteratively simplified until the total number ofpoints in the polygons is no more than number.
-enumber
Set the maximum line-combining error in pixels (also--pixerr). When the model is converted to linesegments, very often there will be cases where a sequence ofmultiple line segments could be converted into a single linesegment with minimal error. This option sets the maximumdistance, in pixels, that a discarded point can be from the linethat replaces it. The default value is a very conservative 1.0;larger values will tend to greatly simplify the model while'smoothing' minor bumps that often happen due to pixel-levelaliasing of the original image. For high-resolution images,-e 2 to -e 10 can really help smooth thingswith minimal ill effect. This feature was added in version20150415.
-fnumber
Set the highpass filter radius (also --filter). If setto 0, the image will simply be thresholded to find edges andlarge dark areas will be modeled as solids. If set greater than0, the effect is to convert constant-brightness regions intooutlines with an edge thickness proportional to thenumber. Generally, a value between 2 and 4 isappropriate for outlining.
-gnumber
Set the image gamma (also --gamma). This allows simpleadjustment of the tonal spread of the image before filteringand thresholding.
-h
Print the command line help message to stderr and exit.
-llevelspec
Set the level threshold or thresholds (also --level).A level directly determines the cut-off between model and void.The number should be a decimal value between 0 and 1(exclusive); for example, '-l 0.5' would set a singlethreshold of 0.5. However, this command line option can also beused to specify multiple levels to create a contoured 3D modelby union. Such a 3D contour, for example, can be used as themodel for a Lithophane. You can give a single integer value (with no'.') to request creation of that many levels with levelthresholds equally spaced between 0 and 1. For example, '-l4' would create four levels. If you want direct controlover the individual levels used, you can instead list them with',' between the threshold values: '-l0.875,0.625,0.375,0.125' produces the same result as'-l 4' -- creating four levels. If more than one levelis specified, -a is implied to ensure that the levelswill align correctly.
-ofile
Set the file name for the OpenSCAD output to file.Normally, the output file name is derived from the inputfilename by replacing any characters after '.' with'.scad' -- but that can be a problem if the image iscoming from a read-only directory, etc. When you specify adifferent name using -o, the name is used precisely asentered, without adding the suffix '.scad.'
-pprefix
Set the name prefix to use for the generated OpenSCAD model(also --prefix). By default, the name prefix is derivedfrom the image file name by removing the portion of the nameafter ., but that might not result in an appropriatename. For example, files can have - in their names, butOpenSCAD modules can't. The resulting model can be instantiatedby prefix();; an individual layer of the modelcan be instantiated byprefix_number(); wherenumber is the level number starting at 1.
-snumber
Set the sub-pixel resolution (also --subres). This isreally a potrace parameter, determining the fraction ofa pixel to which analysis is performed. Larger values are moreprecise, but values between 2 and 10 generally suffice.
-tnumber
Set the 'turd' size (also --turd). This is really apotrace parameter, and the name isn't my fault. Anytraced region smaller than number pixels is essentiallydiscarded from the model.
-v
Enable verbose output to stderr (also --verbose).There are some other messages that go to stdout, but these canbe isolated because they go to stderr. Enabling verbosity alsohas the side effect of leaving temporary files holding theintermediate stages in processing, so it would be appropriate tothink of it as primarily a debugging option.
-xnumber
Set the maximum X axis pixel resolution of the image (also--xres). This value doesn't have as straightforward aneffect on the model as one might expect, but larger values tendto create somewhat more complex models. The iterative complexityscaling is actually implemented by reducing this value andreprocessing.
-ynumber
Set the maximum Y axis pixel resolution of the image (also--yres). Just like X, but for the Y axis..
inputimagefile
The inputimagefile can be in any format understood byImageMagick convert. The portion of the name after .is stripped to create the default prefix for OpenSCAD model componentnames. The output file name is also generated from inputimagefileby removing the portion of the name after . and replacing it with.scad. For example, test.jpg would produce OpenSCADcode names starting with test and would place the output in afile named test.scad.

Examples

Let's start with an easy one: converting a Klingon plaque designfor my parallel processing lab into an OpenSCAD model. Thecommand line was:
The generated OpenSCAD modelfile is fairly straightforward, and the model is simplyklingon_dondewi(). The -f 0 said to keepsolid areas solid. We could also have let the system do highpassfiltering to extract edges:
The generated OpenSCAD model file isfairly straightforward, and the model is again simplyklingon_dondewi(). The original input image and thetwo OpenSCAD 3D models (scaled to 200x200x1) look like:
Ok. That was easy. The second model seems to have done a goodjob of extracting the outlines, except there's also some fluffthat doesn't belong. You can easily fix them using the-t option to remove those little 'turds' (aspotrace calls them). Actually, had I not been sosloppy when making the image, there wouldn't have been a weakbroken edge there for trace2scad to detect in the firstplace..
As of version 20150415, the -e option can really helpto smooth-out the model. This OpenSCAD model, generated by ./trace2scad -f 0 -e10 klingon_dondewi.png, is much cleaner and simpler thanthe ones above. It uses just 387 points, which is only about1/10 as many as the above models, yet the quality of the modelis not clearly inferior; in some ways, it is actually better.
Here's a harder case: my face. For this one, we'll asktrace2scad to make an 8-layer lithophane:
This OpenSCAD model is the resultof converting the following image into the design shown by OpenSCAD.Yes, by default trace2scad sets the object colors based onthe threshold used for each level, so it really does look like amonochrome image.

The Source Code

It's just one file -- a shell script. Thelatest version is trace2scad.All released versions of trace2scad are linked here:
trace2scad20150106
Initial release. Probably buggy? Let me know if you findanything..
trace2scad20150107
Quick clean-up of the initial version. Potrace often generatesline segments that are segments of a potentially longer linesegment, so this version optimizes those out, and now alsoprunes the too-complex trace attempts faster.
trace2scad20150415
Added the -e option to dramatically reduce modelcomplexity and smooth bumps due to pixel-level aliasing.Minor other tweaks.
The only thing set in stone is our name.