Transcript Using AutoCAD features to get the orthogonal projections

Using AutoCAD features to get
the orthogonal projections of a
solid model
Author: Elena Mereuta,
University “Dunarea de Jos”of
Galati, Romania
Abstract
The paper presents the steps to be followed when we
want to get the orthogonal projections from a
complex solid model. After creating the solid
model, the desired view ports, the user has to
create and manipulate the layers on each view port
and the section and make different profiles in order
to get on each projection the desired profiles
(internal or external) and the sections.
Review of the descriptive
geometry methods
• In order to solve the intersection of solid bodies,
the descriptive geometry offers some methods that
lead to the solution. Such methods aim either
acquiring the intersection points of the edges of
one body, with the faces of the other, or acquiring
the intersection segments of the faces of a body
with another body faces. This is the case of the
polyhedrons. When about cylinders and cones, or
spheres the solutions are much difficult to obtain,
as for the necessity of finding a large number of
common points, in order to picture the most
appropriate shape.
The proposed method
Steps:
  Solid modelling of the complex body;
 
The command VPORTS offers the possibility of defining a desired
number of view ports;
 
The system variable Tilemode offers the possibility of changing from
model space to paper space;
 
We use the MVIEW command to get the mobile views in paper space;
the Restore option leads to retrieve the view port configuration previously
saved;
  The command VPLAYER offers the possibility of defining new frozen
layers in all view ports. Their number is according to the necessities;
 
The first view port is for the vertical plane projection and, this time, we
get the profile of the complex model after we change the point of view in
order to get the desired projection. Automatically, two layers will be created:
one for the visible edges, and one for the invisible ones. The same step is
followed for the horizontal and lateral plane projection; we use the DRAWSOLIDS-SETUP –PROFILE command.
Examples
• The intersection of a quadrilateral right prism with the base in the
horizontal plane and a triangular right prism with the base in the
lateral plane that defines the inward shape
The intersection between a circular right cylinder with the base in the lateral
plane and a rectangular right prism with the base in horizontal plane, as
internal shape
The intersection curve of a cylinder and a sphere
The orthogonal projections of a tenon
The intersection of a pipe with a hexagonal right prism
The intersection curve of a torus and a frustum of a cone
Conclusions
• In order to better visualize the intersection curves
obtained in different cases we can use the methods
proposed in this paper that uses the AutoCAD
features for solid modelling of the main bodies.
We create and manipulate the bodies in order to
show the intersection shape. It is necessary to
define the desired projection, to define appropriate
layers and to manage them according to the aims