3D Visualization and Solid Primitive Conceptual Design in AutoCAD

More documents

Recommendations

Info

3D Visualization and Solid Primitive Conceptual Modeling in AutoCAD®any faces, the new solid object will appear identical to the old solid object when shaded orrendered. The thickness of the shell will not be visible. If you wish to create a hollow object withan opening, select the face to be removed (the opening).After selecting the object and specifying any faces to be removed, you are prompted toenter the shell offset distance. This is the thickness of the shell. A positive shell offset distancecreates a shell on the inside of the solid body. A negative shell offset distance creates a shell onthe outside of the solid body. If you shell a solid that contains internal features, such as holes,grooves, and slots, a shell of the specified thickness is placed around those features.CautionUsing the SOLIDEDIT command removes the history from a composite solid. Therefore, theoriginal objects—the subobjects—are no longer available for subobject editing. However, youmay still be able to perform some subobject edits, such as moving the original objects.Creating Composite SolidsA composite solid is a solid model constructed of two or more solids, often primitives.Solids can be subtracted from each other, joined to form a new solid, or overlapped to create anintersection or interference. The commands used to create composite solids are found in the 3DMake control panel in the Dashboard, in the Solid Editing cascading menu in the Modify pulldownmenu, and on the Solid Editing toolbar.Introduction to BooleansThere are three operations that form the basis of constructing many complex solid models.Joining two or more solids is called a union operation. Subtracting one solid from another iscalled a subtraction operation. Forming a solid based on the volume of overlapping solids iscalled an intersection operation. Unions, subtractions, and intersections as a group are calledBoolean operations. George Boole (1815–1864) was an English mathematician whodeveloped a system of mathematical logic where all variables have the value of either one orzero. Boole’s two-value logic, or binary algebra, is the basis for the mathematical calculationsused by computers, and specifically for those required in the construction of composite solids.32
Joining Two or More Solid Objects3D Visualization and Solid Primitive Conceptual Modeling in AutoCAD®The UNION command is used tocombine solid objects, Figure 30. Thesolids do not need to touch orintersect to form a union. Therefore,accurately locate the primitives whendrawing them. After selecting theobjects to join, just press [Enter] andthe action is completed.Figure 30. The UNION command on the 3D Make Control PanelSubtracting SolidsThe SUBTRACT command allows you to remove the volume of one or more solids fromanother solid. See Figure 31. The firstobject selected in the subtractionoperation is the object from whichvolume is to be subtracted. The nextobject is the object to be subtractedfrom the first. The completed objectwill be a new solid. If the result is theopposite of what you intended, you Figure 31. The SUBTRACT command on the 3D Make ControlPanelmay have selected the objects in thewrong order. Just undo the operation and try again.Creating New Solids from the Intersection of SolidsWhen solid objects intersect, theoverlap forms a common volume, aspace that both objects share. Thisshared space is called anintersection. An intersection can bemade into a composite solid using theINTERSECT command. See Figure 32.A solid is formed from the commonFigure 32. The INTERSECT command on the 3D Make ControlPanel33
Page 1 and 2: 3D Visualization and Solid Primitiv
Page 31: 3D Visualization and Solid Primitiv
Page 41: 3D Visualization and Solid Primitiv

3D Visualization and Solid Primitive Conceptual Design in AutoCAD

Create successful ePaper yourself

Delete template?

Save as template?