Difference between revisions of "Sandbox:Piffpoof9-0"
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Revision as of 19:45, 13 February 2016
This group of tutorials is intended to provide:
- an overview of certain workbenches and the workbench approach to modeling used by FreeCAD
- some guidance on choosing between the Part and Part Design workbenches in modeling
- some skills in modeling using the Part and Part Design workbenches
Workbench Approach to Modeling
3-dimensional modeling incorporates a number of discrete approaches to the problem. In FreeCAD these are represented by the individual workbenches. More or less, the product of different workbenches can exist side by side with the output of different workbenches. At any point during modeling the user can switch to a different workbench. This suite of tutorials will deal with the Part and Part Design workbenches as well as the Sketcher workbench as used through the Part Design workbench.
Selecting Between the Part and Part Design Workbenches
Focussing on the Part and Part Design workbenches, it is sometimes difficult to decide which workbench to use in modeling. It is worth remembering that the workbenches can be used interchangeably, the output of one blends in perfectly with the output of the other. There are a number of factors which can effect the choice:
- modeling with the Part workbench typically involves geometric solids (e.g. Cylinder, Square, Sphere, Cone Solid), these shapes are then manipulated using Boolean operators (e.g. Cut, Fuse), or operations such as Pocket and Thickness
- modeling with the Part Design workbench is often oriented around 2-dimensional Sketches which are then used to define 3-dimensional shapes. For shapes that are intricate and don't easily model with geometric solids (such as those offered by the Part workbench) using the Sketcher workbench (either on its own or through the Part Design workbench) can often be easier.
- finally, your personal preferences - over time you may come to prefer one workbench over the other
- and lastly. modeling is ultimately exploring the problem space, everyone has encountered a problem where they started with one approach and through that, learned enough about the problem and its potential solutions to realise that they would be better starting again with another workbench, and another approach.
Developing Skills in Modeling with the Part and Part Design Workbenches
Modeling skill for the Part and Part Design workbenches will be developed in the detailed tutorials.
The 6 tutorials fit together as a suite. This is nominally the first tutorial but really it is an overview of what follows. The task of these tutorials is to demonstrate different modeling approaches to a problem, and the interchangeability of the modeling outputs. The problem (or objective) is to model a lock housing, a key to fit into that lock housing and then to animate that key. We will not be modeling anything in the lock housing, no internal parts at all. Are outputs will all be cartoon-like as we are demonstrating the modeling process, not real world items.
The following diagram shows the 4 stages - remembering the first stage is this overview tutorial. The first stage has 3 alternatives to follow as part of the first step. The second stage, which is modeling the key, has 2 alternatives. And finally for the third stage there is only one animation alternative shown. There are other ways to animate the key but they are best left to tutorials dealing with the Python programming language (which are listed at the bottom of this page).
This tutorial offers alternative paths through it. It is not expected that each tutorial need be studied. Only one alternative from each stage needs to be used. And in fact, as each tutorial has example files, a stage can be skipped over and the example file used for the next stage. Each alternative creates the same output. But the output is interchangeable with the other alternatives of that stage. The differences are due to different modeling methods creating slightly different object models.
This tutorial suite offers:
- intermediate level instruction on the Part and Part Design workbenches
- the ability to compare different modeling techniques applied to the same problem
- example files to facilitate modification or disassembly of models
- a simplistic example of applying Python coding to manipulate a model (in this case simply ot animate the key)
The diagram shows the structure of the tutorials and the paths through them - remember a stage can be skipped over by simply using the example file from it.
Selected Problem for Tutorial
The selected problem for these tutorials is captured in the 2 drawings below. The first is a housing or box for a lock, the second is the key to enter the lock. We will not be modeling the internal details of the lock, the lock housing will simply be a box with an empty interior and the holes for the key as show in the drawing.
Lock Housing drawing
Where the text Note: appears, it denotes that the section of text is covering an important or key section. An example is:
Note: The object has now been safely saved.
Where the text Hint: appears, it denotes that the section of text is covering actions that till be advantageous later, or in another situation. An example is:
Hint: By positioning the object in this fashion, it will be perfectly placed for subsequent operations.
Example files accompany the tutorials. They are listed sequentially in the Summary box at the top of the tutorials. They are also available in the narrative text.