Introduction – Вступ#


Об’єкти, нарисовані за допомогою PDT та виміряні з MeasureIt

PDT призначений працювати у Blender 2.8 та всіх наступних його збірках. Немає версій цього додатку для попередніх версій Blender.

The key objective is to make precision modeling easier and more capable in Blender in order to allow Designers of all genres to model accurately.

Interestingly – Цікаво#

There is definitely a difference in the way that «CAD Designers» and «Polygon Modelers» work. Polygon Modelers, the traditional Blender users, tend to start off with a basic primitive 3D mesh, like a Cube, or a Cylinder, then start to add Edge Loops to cut it up, to extrude sections to make it more complex, to add «holes» and then work these. They will often use Sub-Division modifiers to make the model more detailed, whereas CAD Designers consider these to largely be unsuitable and reduce accuracy. This means more vertices in the mesh from CAD modeler, but probably about the same after all has been taken into account.

CAD modelers would virtually never trace off a previous drawing, or photograph to model something, they will always work from quoted dimensions only. To this end think about a drawing at a scale of 50:1 - a line of width 0.5mm is effectively 25mm thick in the real world. Many drawings carry the mantra «Do Not Scale» - this is for a reason, old tradition hand-drawn drawings are not necessarily accurately drawn in the first place!

Традиційні дизайнери САПР CAD Designers (я використовую термін «САПР» – «CAD» для того, що вважається автоматизованим проєктуванням Computer Aided Design, продуктом програм, як-от SolidWorks, AutoCAD, MicroStation тощо) схильні робити точну плоску петлю, як-от перед полички чи стіна будівлі, потім видавлювати або «обтягати» («loft») це в 3D сіть. Довгий час вважалося, що такий підхід веде до більш точних моделей, які можна було б, наприклад, використовувати в 3D друку.

PDT aims to introduce this method of working into Blender, for the benefit and inclusion of all genres of CAD Designers and to augment the tools for the Polygon Modeler. It has been developed by a former Mechanical Design Engineer with many years experience in drawing offices, using hand drawing and CAD techniques.

Nomenclature – Номенклатура#

There is also the situation where CAD Designers and Polygon Modelers use different terms, like Absolute versus World coordinates, Delta versus Incremental, Directional versus Polar. Primitives themselves are also named differently, Vertices, Edges & Faces versus Points, Lines & Polygons - PDT takes care of this by providing a file that users can edit to input their own terms, including their own languages.