In the field of materials working (such as marble, glass and wood) one usually come across the problem of either copying a pre-existing object or obtain a DXF file from a template or a handmaded drawing. The software application ShapeToDXF is the answer to this problem. In particular, ShapeToDXF is oriented to the digitalization of 2D planar shapes such as kitchen tops, bathroom tops, tables, windows sills, fireplace mantels and column profiles. In the same way, ShapeToDXF is able to generate a DXF file from a raster image such as a bitmap file.
Figure 1- Image of a template
Figure 2 - DXF extracted from the template
The DXF file obtained from ShapeToDXF is usually imported in a CAD/CAM system where the user generates the tool path necessary for the CNC machine to produce the object.
ShapeToDXF leans either on a professional digital camera or an industrial digital camera that is used to acquire the image of what the user is going to copy. The image is processed by ShapeToDXF that, in a few minutes, generates the DXF files.
Figura 3 - Professional digital camera and industrial digital camera
Description of the application
A digital image can be seen as a grid of points, each one having a different color. ShapeToDXF is able to recognise the points that delimit the object displayed into the image and from these generates the DXF file.
ShapeToDXF doesn't restrict itself to extract some points from an image but it transforms the object contours into mathematical entities, in particular lines and arcs. The mathematical entities have the function of regularizing the contours and are the same the the user, without ShapeToDXF, should have to obtain manually.
Another benifict of converting the contours into mathematical entities is the opportunity of managing geometrical constraints such as tangencies, parallelisms, orthogonalities and symmetries. These constraints are identified automatically by ShapeToDXF either with the purpose of obtaining an accurate drawing or correcting the defects of a handmaded template. The image of Figure 4 shows a case where the above constraints have been taked into account to generate the DXF file.
Figure 4 - Example of geometrical constraints
The scale of the drawing can be set either manually, by selecting two image points at known distance, or automatically with the use of a marker that has to be placed near the object to be copied. Another scale factor can be set to manage templates that come with a lower scale with respect to the object to be made.
In the base version of ShapeToDXF it is important that object (or template) and background present distinct and uniform colors. A simple tool of ShapeToDXF allows to delete elements of the background that can eventually interfere with a correct identification of the object displayed into the image. However, it is possible to ask for a version of ShapeToDXF able to manage complex objects with non-uniform color.
According to the particular digital camera used and acquisition method, ShapeToDXF is able to identifying the object contours with an accuracy up to 0.1 mm. The user that possess a CNC machine can take advantage from it by installing the camera on the machine itself and by taking more than one images of the object from a lower distance. The differents images are merged into a new image of higher resolution so to obtain an higher accuracy.
The image of the object can be acquired in different ways with respect to the necessities and the availabilities of the user. As said before, in case the user has a CNC machine, the camera can be installed on the machine itself in such a way that the camera looks at the working bench from up above. If this is not the case, the camera can be installed on the tripod supplied with it.
It is also possible to acquire, from any angulation, images of objects that lean on a plane. A function of ShapeToDXF allows to correct the perspective distortion as shown in Figure 5.
Figure 5 - Perspective correction
What you can do: digitalize (transform from raster to vectors) 2D shapes that must be reproduced in marble, granit, glass, wood and other materials;
What you can copy: pre-existing objects, templates (cardboard, millboard, wood or iron), drawing on paper, drawing on blackboard, raster images (bitmap, jpeg);
Content of the basic bundle: ShapeToDXF software application + digital camera with lens + tripod + scala marker;
Content of the advanced bundle: ShapeToDXF software application + digital industrial camera + lens + software application for merging multiple images + camera support for CNC mounting + scala marker;
Accuracy: up to 0.1 mm, depending on thecamera used and acquisition method;
Elaboration time: from 2 to 5 minutes for each contour;
Identification of the contours of one or more objects displayed into an image;
Contours regularization (elimination of the indentation);
Vectorization of the contours (from raster image to DXF file);
Elimination of extraneous elements of the image background;
Identification of geometrical constraints (tangencies, parallelisms, orthogonalities and symmetries);