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Technical Drawing  Interpenetration  Line PenetrationFirst of all we are going to break Interpenetration down into
its most basic element, where we find the point where a line
penetrates a flat surface or plane. Below is the
dimensioned diagram you need to draw in order to practice this
exercise.
Generally it is important in Technical Drawing to label points of importance, but in Interpenetration it is doubly important. This will become more noticeable as the drawings become more complicated but it is good practice to start the way you mean to continue. From the Plan and Elevation you should be
able to see that you have a plane surface at an angle to
the Vertical Plane (VP). You are told a line L,
50mm above the Horizontal Plane (HP) and 45mm out from
the VP penetrates the plane surface. You are asked
to find where this penetration occurs.
You cannot see where the line penetrates the plane in the Elevation, but in the Plan you can see where the penetration occurs. This leads us to the solution of the problem. Remember that when you are setting up this question draw all of your lines very lightly and label the points. Below you can see how to complete the question. Set up your drawing according to the
given dimensions, remembering to label your points and
draw lightly.
In the Plan you can see where the line
intersects with the plane. Project this point onto
the line in the Elevation.
You should be able to see from the
Elevation and Plan where the line is behind the plane
from the direction that you are looking at it. You
do not need to draw in hidden detail unless you are
asked to do so in your question, but we do it here for
clarity.
You can now line in heavily the answer to
your question.
This was a very simple question but it shows the very basics of Interpenetration. If you can understand what is shown above then you can solve any Interpenetration question with a little bit of hard work. It is simple a case of finding, in one view, where a line, edge or generator, cuts through a surface and projecting that point to another view. Often the hardest chalenge is visualing your solution. Remember to draw carefully and neatly to reduce this problem. 


