Tracing a picture with LibreCAD - tutorial 7 part 2 Video Lecture - LibreCAD

although scary Fox and we're back on the
tutorial number seven excuse me uh
anyhow as you see I've brought up a
screen right now and there's a few
things that I wanted to talk about that
we hadn't dealt with yet the question
come up to me can i what can I do as far
as extend a trim with the case of a a
spline spline curve so aside the best
way to do it is just to try it and now
I'm going to share that with you so I'm
gonna go to the trim function and I am
gonna click on the spline to be my
limiting entity and beggared heck it
works same thing I can extend to using
it however if I click on another line
and try to extend a spline it will not
extend and that makes sense because the
splines based upon those points there
but anyhow now we know okay the other
one I want to talk about we're going to
be dealing with an ellipse later today
so let's show how to do an ellipse there
really is only one ellipse function the
other ones just an arc so the ellipse
function you need to know where the
center of the ellipse is and that's
going to cause us a problem when we get
back to the car so once you do that then
it says find the major axis that's the
big part of the circle because an
ellipse basically is a squished down
circle one side squished in comparison
to the other and now we're supposed to
find the minor axis so we can draw it
and we've drawn our lips okay the other
thing and I want to show you is the
offset function
which is actually four lines but there
is one four circles and so we got a
circle Lego concentric which is
basically an offset
we got a distance of four and I think I
look okay and you see I can draw
concentric circles okay let's try that
with a line will go to line and we'll do
it offset and you see that it works for
the lines and we've done that a bunch in
the past but it also works for circles
so the question is will work for ellipse
and no it will not and that makes sense
because a bigger ellipse would not have
the would not be the same throughout it
would be bigger at the at the major axis
than it would be at the minor axis
excuse me I seem to be draining out here
I am going to delete this document
because we don't need it anymore and
we're just going to close it without
saving okay now I'm gonna deal with my
car video car picture and you see that
I've moved it into another directory so
I could find it quicker if I pull that
up
I get the car picture and I was curious
if you could send that file to somebody
else if you wanted to and they would get
both the picture and the and the drawing
that was created so let's see what
happened if I did it in another
directory and it works so that kind of
answers that now what happens if I
change the name of this file so we're
going to rename it
and now we go to picture file to the
drawing and all we get is the car body
the sketch by the way I added a whole
bunch more heavier life anymore seems to
be spent watching those little
horizontal bars prove that something's
happening and that happens when I save
these videos so that didn't work well
I'm curious now will it work on this one
or is it referencing this picture right
here so I go to this test when I created
and it does work so it looks as if if
you store the both the picture and the
drawing file in the same directory and
then if you sent it on to someone and
gave them instructions to put both of
them in the same directory it would work
okay
so we'll go back to this one as our real
one we'll rename the file the same as
the one up above
and now it should work and it does okay
the other thing I know one to show you
is if we wanted to draw these tires on
this or the wheels and the tires on this
car either probably the best thing to do
is an ellipse and the reason we have to
use an ellipse is that we've got
perspective going on because we're
looking at the corner of this and not
straight on at the side things are
getting farther away so they're getting
smaller and that's because our our
vision tends to expand as it gets
farther out you know it's basically a
cone that goes out from our eyes and
from a camera lens also and if you think
about any pictures you've seen of
railroad tracks where the tracks go out
there and they seem to come together way
out there at a distance that's exactly
what's going on in this pitcher only
it's much smaller because it's a lot
closer but that means that the back in
the front of this is going to have is
basically the minor axis the top and a
bottom or the major axis it also means
that Center has not Center and that's
going to be a little bit of a hassle so
we're gonna tip to draw this and I'm
going to go back to go to you and I just
turned it off to level zero and as I do
that I go to right here I'm getting
raised I got to click the button and I'm
going to draw the center of this about
on the center at horizontal will be on
the center vertical will be my guess and
now I draw my ellipse and it looks as if
I missed it so we will start all over
five sinner will go a little bit more
toward the front okay now we'll do the
major axis and we're closer I'd say not
quite close enough
depends on how Piketty you want to get
and that's looking pretty close there
for the top and the bottom so we'll go
ahead and set that and now we have to do
the minor axis and we've got our our
what I always called the rim that's
actually the most people call it the
wheel
we'll have it a little bit easier a
whoops I just open up something so we'll
have to wait a minute well exit that and
we'll now do another one and our Center
will be exactly on the center of the
other as a matter of fact we can
probably choose Center and that way
we'll be exact
then we'll go to Oh free free selection
for you exactly what they call that and
we'll go here and we have our tire I'll
see what it looks like in the pitcher
return the pitcher off that doesn't look
too bad does it
we'd have to draw the other part of it
we could try doing that what we would
have to do we will draw that I believe
the center of that will be a little bit
in front of the other centers and we
guess that tire bottom will be at the
same bottom as it was before but our
minor axis be on out here and I didn't
do a very good job so let's go back to
Center we need to set this thing a
little further forward
that's gonna be a skinny tire well maybe
not ice-cold look about right then
obviously we're gonna have to trim it so
you can get to where you need to go and
basically it takes some doodling to do
it trying to think if there's anything
else I need to talk about on this one we
could then let's do that but first let's
delete that last ellipse Oh we'll go
ahead and we'll turn off the picture for
a moment and we'll see if we can do a
little better job on our you know I've
got some time left from this thing yeah
not a lot what we could do is delete
this part of the wheel will and then try
putting in a spline curve I don't think
I'll have time to finish that in this
video so you got the idea and you kind
of see where the results would be
obviously I need to do a little work
right on this this this part of the
grille and then you know I could you
keep right on going and depends on how
far you want to take this thing a quick
quick quick statement about where we
used it when I was in fact in the one
consulting job one case I had to do
lightening rods on a building and we had
to show on that building to give the guy
an idea of what he was going to have to
estimate where all of the protrusions
were coming out of the root for all the
vents all of the things that stuck up
that was going to be a pain on that
particular building
luckily the CAD person that I had knew
that there was a a aerial photograph of
that building and she was able to pull
up that aerial photograph match it up to
a door scale drawing and on that one you
could actually scale up and scale down
the
the pitcher she scaled it so that it fit
the top of the drawing of the building
and then was able to sketch in all of
the patricians out of it
in another case took a photograph of a
wall directly onto that wall and then we
were going to have to mount an
electrical box on the wall so all we did
was we referenced from some things that
were in the picture the number of feet
so we had to take a couple of
measurements and we put those on there
as dimensions and we roughed in a box
and said mount the box right here so
that is a use for it as far as using it
in an actual drafting environment right
now we're kind of doing artwork but you
got an idea of wanted to do I can't tell
you where you'd want to use it that's
all up to you but it's one more tool
that you have in your toolbox anyhow I
think I've done enough damage on this
one appreciate you listening this is
Gary Fox great