Part and PartDesign/ru: Difference between revisions
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Это условие остается таким до тех пор, пока оператор не использует некоторую операцию для их объединения (обычно логическое значение, которое добавляет или вычитает их). |
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This condition remains so, until, the operator uses some operation to combine them (typically a Boolean that adds or subtracts them). |
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Каждое начальное твердое тело остается доступным отдельно, и операция создает новый объект. |
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Each starting solid remains accessible separately and the operation creates a new object. |
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The take away is the single solitary solid bit and the combining them bit. |
The take away is the single solitary solid bit and the combining them bit. |
Revision as of 15:59, 22 August 2022
Обзор
В течение многих лет широко обсуждались различия и последствия использования верстаков Part и PartDesign.
Рекомендуется использовать один из верстаков, пока пользователь не освоится с ним, а затем изучить другой. Также обычно рекомендуется, чтобы новые пользователи не смешивали их, пока не будут понятны последствия этого.
Давайте поговорим об этих последствиях.
Коцепции Верстака Part
Верстак Part это по сути моделирование в стиле КТГ. Оператор комбинирует различные примитивы, чтобы в конечном итоге получить представление желаемой формы. (Фактически, Верстак Part идёт на один шаг дальше, чем просто примитивы и позволяет оператору использовать операцию эскиз+выдавливание (или эскиз+вращение, лофт, развертку ...) для создания случайных форм.) При создании каждого примитива или фигуры он не имеет отношения к другим созданным объектам (кроме эскизов и их вложений), является единственным одиночным твердым телом.
Это условие остается таким до тех пор, пока оператор не использует некоторую операцию для их объединения (обычно логическое значение, которое добавляет или вычитает их).
Каждое начальное твердое тело остается доступным отдельно, и операция создает новый объект.
The take away is the single solitary solid bit and the combining them bit.
Коцепции Верстака PartDesign
In the PartDesign Workbench the Body object is constructed directly as a single solitary cumulative solid.
The 1st step in a body must be a block of material, either from an additive primitive or an extrusion from a sketch, or an imported shape (then called Base Feature).
This initial block of material will be changed sequentially until the desired final shape (solid) is obtained.
It is cumulative in the sense that each operation adds or removes material.
By default, the "tip" of the body - unless there is a voluntary change in the visualization of a particular feature - is the last operation performed on the body. This is the current and visible state of the body, ready to be changed again by new feature.
Any function under the body represents the cumulative shape of the solid from the 1st feature to the feature considered.
So to have the complete solid, on the one hand the Tip feature must be the last stage of the construction of this solid, and on the other hand it is the body which must be selected and not a stage of its construction.
This will make it possible, in the event of a modification, to always have the last version of the solid represented.
Note and additions :
At each time of the construction, the last function used is the "Tip", which can be defined too as "active stage in the construction of the object" or "stage preceding the next action in the construction of the object". When the object's drawing is complete, Tip is naturally the last stage or feature of the construction. But if desired, in case of forgetting, any feature of the construction can be provisionally declared as Tip: it then becomes the step preceding the next action in the construction of the object, which means that new feature(s) can be inserted anywhere in the construction, on condition not to create any incompatible with the suite.
When everything is finished, you have to redeclare the last feature as Tip, which corresponds to the finished object.
This image shows a Body. It is a cumulative solid that consists of a padded sketch and a cone primitive. This is a single solid.
If Tip on Pad, the pad can exist separately, but if Tip on Cone, the cone cannot exist separately (Tip on cone = pad + cone).
(Another thing mentioned often is a Body MUST be a single contiguous solid. This means all geometry created by a feature in the Body must touch it's predecessor.)
The Ramifications
Although not recommended for newcomers, it is possible to combine tools from Part workbench and PartDesign workbench, provided you know what you are doing. For example :
People get caught when they attempt to use some feature under the Body (rather than the Body itself) as one selection of a Part Workbench Boolean operation. This is a problem, because the selected feature does not represent THE complete solid.
In a sense, from a Part Workbench standpoint, the Body represents another primitive. So, using a Body (remember it is a proxy for the tip) and a Part Workbench object to do a Boolean is valid. But the resulting object is a Part WWorkbench object. And, thus PartDesign Workbench tools can't be used on it any longer.
And, it can get even more complicated. If you create a new Body and drag the result from the previous paragraph into it, a BaseObject is created. And you can go off an use the PartDesign Workbench tools on it.
The Caveats
There is a caveat with the Tip and it's representation of the single solid in the Body. If the tip is a subtractive feature and is used in a dress up operation, for instance a Mirror, the Mirror is operating on the underlying feature (a pocket for example). Thus the cumulative solid is not mirrored, but the subtractive feature is. The result of this must create a single solid.
In this example, a mirror of the tip (which is the pocket of the slot) around any of the base planes, or even a face of the solid will not produce a mirrored solid of the entire model. (In fact, it will produce a Mirrored feature in the tree that is essentially empty.)
In this example, a mirror of the tip (which is the pocket of the slot) is performed around the datum plane and produces a mirrored slot:
See the PartDesign Mirrored tool wiki page for more information.
Сравнение
You can see below the same example built with each of the two workbenches. Of course, there are always several possible construction timelines with each workbench.
In PartDesign workbench | In Part workbench |
---|---|
01- New body > New Sketch in XZ plane | 01- Sketcher workbench > Sketch in XZ plane |
02- Revolution / Z | 02- Revolve / Z |
03- New Sketch in XY plane | 03- Sketcher workbench > New Sketch in XY plane |
04- Pocket | 04a- Extrude |
04b- Cut | |
05- New Sketch in XZ plane | 05- Sketcher workbench > New Sketch in XZ plane |
06- Pad sym/XZ | 06a- Extrude sym/XZ |
06b- Draft Polar Pattern | |
06c- Fusion | |
07- New Sketch on base planar face | 07- Sketcher workbench > New Sketch in XZ plane |
08- Hole - counterbore | 08a- Revolve |
08b- Draft Polar Pattern | |
09- Polar Pattern of Hole and Pad | 09- Cut |
Compare the construction trees in the two workbenches as well as their organization and reading timeline :
10- Construction tree in PartDesign workbench | 10- Construction tree in Part workbench |
Заключение
Part and PartDesign workbenches can be used together with some care, creating quite complex models.
- Примитивы: Куб(Параллелограмм), Конус, Цилиндр, Сфера, Тор, Полый цилиндр,Примитивы, Связующие формы
- Создание и правка: Выдавливание, Построение фигуры вращения, Отражение, Скругление, Фаска, Создать плоскость из граней, Ruled Surface, Профиль, Sweep, Section, Cross sections, 3D Offset, 2D Offset, Создать полый объект, Projection on surface, Прикрепление
- Булевы операции: Соединить, Разорвать связь, Compound Filter, Булевы операции, Cut, Fuse, Common, Connect, Embed, Cutout, Boolean fragments, Slice apart, Slice, XOR
- Измерительные: Measure Linear, Measure Angular, Measure Refresh, Clear All, Toggle All, Toggle 3D, Toggle Delta
- Инструменты структуры: Part, Group
- Вспомогательные инструменты: Create body, Create sketch, Edit sketch, Map sketch to face
- Инструменты моделирования
- Инструменты данных: Create a datum point, Create a datum line, Create a datum plane, Create a local coordinate system, Create a shape binder, Create a clone
- Аддитивные инструменты: Pad, Revolution, Additive loft, Additive pipe, Additive box, Additive cone, Additive cylinder, Additive ellipsoid, Additive prism, Additive sphere, Additive torus, Additive wedge
- Субстрактивные инструменты: Pocket, Hole, Groove, Subtractive loft, Subtractive pipe, Subtractive box, Subtractive cone, Subtractive cylinder, Subtractive ellipsoid, Subtractive prism, Subtractive sphere, Subtractive torus, Subtractive wedge
- Инструменты трансформации: Mirrored, Linear Pattern, Polar Pattern, Create MultiTransform
- Отделочные инструменты: Fillet, Chamfer, Draft, Thickness
- Бинарные: Boolean operation
- Дополнительно: Migrate, Shaft design wizard, Involute gear
- Инструменты контекстного меню: Set tip, Move object to other body, Move object after other object
- General: Create sketch, Edit sketch, Map sketch to face, Reorient sketch, Validate sketch, Merge sketches, Mirror sketch, Leave sketch, View sketch, View section, Toggle grid, Toggle snap, Configure rendering order, Stop operation
- Sketcher geometries: Point, Line, Arc, Arc by 3 points, Circle, Circle by 3 points, Ellipse, Ellipse by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola, B-spline by control points, Periodic B-spline by control points, B-spline by knots, Periodic B-spline by knots, Polyline, Rectangle, Centered rectangle, Rounded rectangle, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Regular polygon, Slot, Fillet, Corner-preserving fillet, Trim, Extend, Split, External geometry, Carbon copy, Toggle construction geometry
- Sketcher constraints:
- Geometric constraints: Coincident, Point on object, Vertical, Horizontal, Parallel, Perpendicular, Tangent, Equal, Symmetric, Block
- Dimensional constraints: Lock, Horizontal distance, Vertical distance, Distance, Radius or weight, Diameter, Auto radius/diameter, Angle, Refraction (Snell's law)
- Constraint tools: Toggle driving/reference constraint, Activate/deactivate constraint
- Sketcher tools: Select unconstrained DoF, Select associated constraints, Select associated geometry, Select redundant constraints, Select conflicting constraints, Show/hide internal geometry, Select origin, Select horizontal axis, Select vertical axis, Symmetry, Clone, Copy, Move, Rectangular array, Remove axes alignment, Delete all geometry, Delete all constraints
- Sketcher B-spline tools: Show/hide B-spline degree, Show/hide B-spline control polygon, Show/hide B-spline curvature comb, Show/hide B-spline knot multiplicity, Show/hide B-spline control point weight, Convert geometry to B-spline, Increase B-spline degree, Decrease B-spline degree, Increase knot multiplicity, Decrease knot multiplicity, Insert knot, Join curves
- Sketcher virtual space: Switch virtual space
- Additional: Sketcher Dialog, Preferences, Sketcher scripting
- Начинающим
- Установка: Загрузка, Windows, Linux, Mac, Дополнительных компонентов, Docker, AppImage, Ubuntu Snap
- Базовая: О FreeCAD, Интерфейс, Навигация мыши, Методы выделения, Имя объекта, Настройки, Верстаки, Структура документа, Свойства, Помоги FreeCAD, Пожертвования
- Помощь: Учебники, Видео учебники
- Верстаки: Std Base, Arch, Assembly, CAM, Draft, FEM, Inspection, Mesh, OpenSCAD, Part, PartDesign, Points, Reverse Engineering, Robot, Sketcher, Spreadsheet, Surface, TechDraw, Test Framework