[Pythoncad-developer] Draw in oo mode

[Paolo Z. <zam...@gm...>]

Hi developers,

Let read the follow idea!

Some days ago I bring my chief a draw, and he told me: “next time it’s
better if you bring me a white paper with some random lines on it, so I
can fix them on it!”. All times I mind about a list of entities in a
document I ask myself: Now who does fix them?

All you know everything about the difference between procedural
programming and object oriented programming. And no matter, it is most
useful the second one. Then, why we draw in procedural mode instead of
oo mode?

Geometric entities in a draw are the same as the lines in a printed
program. Even less complex ones. In fact if I change the order in a
printed code line in a program the program won’t even start, instead if
I change the order of the entities in a draw nothing wrong happens. The
entities in a drow are free from semantics and structure!

All of us think about 3D drawings as special ones because of are visual
and recognizable. But 3D drawing is special because the designer build
and handle objects, and the computer software manage them easily.

If you want to do it in 3D you don’t need to do it. You can build,
handle and manage objects even in 2D environment. The geometric entities
are 1D objects in a 2D environment.

The objects we can handle are 2D surfaces in a 2D environment. The
surface is the result of a 1D entity closed frame. I mean “frame” as a
chain of entities: the end point of an entity is the starting point of
the next entity. 

In a surface you can describe an inside or an outside, a filled side or
an empty side. And you can have a function applied to the surface. You
can have a hole on a surface. Even you can hide a surface on others and
sketch the shadow on it. You can link two surfaces, intersect, add or
subtract each others.

The final result of all these functions is the projection (view) of the
physical object, and you can relate it with other projection of the same
object.

The projections are positioned on the sheet and dimensioned. You can’t
handle 1D entities outside a surface because if you do it you would
create a non sense. The designer just have to mind about draw surfaces
instead of draw random entities.  

You can do even more

Each function own the tree of functions who generate it. You can
generate a function and figure again it’s projection. You can even
change the input surfaces of the functions and figure again it’s
projections. The surfaces  patterns may be parametric, I change one
parameter and figure again the relative projection. 

One projection may be set in relation to the others. In this way if you
move or change the projection even the son projections move or changes. 

It’s a new world!

Why do we go on as usual and manage a simple list of entities?

 

Best regards..

Paolo Zambetti