Instead of dimensions, Constraints are used to limit the degrees of freedom of an object. This gives great flexibility in the design process. They are in effect "floating" and can be moved, stretched, rotated, scaled, and so on. Objects can be drawn loosely, and as long as they are unconstrained, can be modified. Objects do not need to be drawn exactly as you intend to, because they will be defined later on by constraints. When you've finished drawing your geometries, you add dimensions to them. Or you will draw your line without regard to its position, and move it afterwards. If you want to draw an horizontal line 100mm in length starting at (0,0), you activate the line tool, either click on the screen or input the (0,0) coordinates for the first point, then make a second click or input the second point coordinates at (100,0). Objects are drawn precisely to the intended size or dimension. Orthogonal (2D) views are drawn manually and intended for producing technical drawings (also known as blueprints). The traditional way of CAD drafting inherits from the old drawing board. To explain how the Sketcher works, it may be useful to compare it to the "traditional" way of drafting. A constraint solver calculates the constrained-extent of 2D geometry and allows interactive exploration of the degrees-of-freedom of the sketch.Ī fully constrained sketch Basics of constraint sketching The Sketcher workbench features "constraints", allowing 2D shapes to follow precise geometrical definitions in terms of length, angles, and relationships (horizontality, verticality, perpendicularity, etc.). Moreover, together with the PartDesign Workbench operations, the Sketcher also forms the basis of the feature editing methodology of creating solids. Together with boolean operations defined in the Part Workbench, the Sketcher forms the basis of the constructive solid geometry (CSG) method of building solids. Generally, a 2D drawing is considered the starting point for most CAD models, as a 2D sketch can be "extruded" to create a 3D shape further 2D sketches can be used to create other features like pockets, ridges, or extrusions on top of the previously built 3D shapes. Unfortunately, it strips the object of any link to the cylinder, and the Edge won't be editable.The FreeCAD Sketcher Workbench is used to create 2D Sketches intended for use in the PartDesign Workbench, Arch Workbench, and other workbenches. Then add two constraints to your circle: an equality constraint between the circle and the magenta reference circle geometry, and a coincident constraint between the two circle centers.īut at this point, it would save time to directly create a new sketch on top of the cylinder.īut the Part Sweep tool does not only accept sketches, it allows other 2D geometries such as basic "Edges".Īn alternative step #2 would be to use the Draft Downgrade tool twice on the Draft2DView object to get an Edge that will be recogninzed by the Sweep tool. Once in edit mode, use the Sketcher External geometry tool to copy the outer edge of the cylinder. What you can do is to use the Sketcher MapSketch tool to map the sketch on the top face of the cylinder. It won't be linked to the cylinder, and there won't be any constraint in the sketch, you need to add them yourself. The sketch will be on the same plane as the Shape2DView object, which is the XY plane.
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