Scaling by factor and by reference in AutoCAD

hello there in this tutorial I'm going to show you how to scale a drawing and I'm going to show you how to do that using two different methods between both methods you should know everything you need to know about scaling a drawing so here we have a floor plan and if i zoom in here and have a look at some of the dimensions between the grid lines we've got five thousand nine hundred and twenty millimeters four thousand three hundred and thirty five millimeters so I standard enough grid intervals but this particular floor plan has been generated from a PDF image so we have no real control over what scale that comes in at when we import it as a PDF so what we want to do is we want to scale it so that when we measure something under drawing it actually measures those dimensions so I want to show you something here I'm just going to put a dimension on here and I'm going to change my dimension styles for a second because this I've had a look at this drawing already and I know that it's it's quite a large drawing so I'm just going to change the size of my text to something like two thousand units now I know that's quite large but I will just just bear with me for a moment and you'll see why so it's gonna go okay to that now what I want to do is have a look on here according to the PDF the grid interval between t1 and t2 should be 5 meters 920 now if I just try putting a linear dimension on there what I'm getting is actually four hundred and sixty six thousand so it's way off I mean that's that's a huge difference between those two so obviously when you bring it in as a PDF you know you're gonna find these little issues somewhere along the line so I'm going to show you how to fix that now what I've done is I've drawn a horizontal line this red line here between T 1 and T 10 just stronger as a line between the two extreme left and right hand sides I've also used my calculator I've added up those dimensions that are written on there and it comes to 39,500 so up here what I've done is I just drawn a line and if I take a dimension on that that line is 39,500 so essentially what I have is I have a red line up there which is the correct length overall length of the building and what I have here is a red line here which represents the same extremities but obviously at a much different scale so I'm just going to show you how to scale using the numbers first of all okay so the keyboard entry for this is the letters SC and then press Enter now I have a look at your command line it says select the objects I'm just going to draw a line over the bit that I'm interested in I'm being careful here now I'm not drawing my box over that little red line up there I'm just throwing it over the image pressing enter because I finished selecting objects look down here now it says specify the base point just really matter at this stage the base point but I'm going to select the bottom of the bubble 41 by doing a left click now you see it says specify scale factor so if I want to make my image smaller I have to use a decimal point so I'm going to type in 0.01 effectively that's going to shrink that image down to 1% of water currently is so when you type in 0.01 and press Enter you get the same drawing but everything has been shrunk down now I'm gonna change my dimension styles at this stage I needed to make it overly large so that you could see those numbers but I'm going to change that now so I'm going to click on that and delecious and I'm just going to go up here to my dimensions and I'm going to modify my style and instead of having a 2,000 units text size I'm going to put in something like 500 I'll make it a little bit easier to see so if I do a linear dimension now from T 1 over to the right-hand side at T 10 my drawing now is 311 sorry 30 1,100 units it's close to what I need and if I actually what I might do is I might move that up a little bit closer to the reference line that I've drawn so M and enter select that and enter scrolling out a little bit here and I'm just going to move it up a little bit closer so I can see the two things on the screen together so what I have up here is the reference line which has drawn the correct length from T 1 to T 10 and what we have down here is just a scaled by number version of what we had a few moments ago so I just took a guess I guessed the 0.01 scale it's not quite right it's close to is not quite right what I might do is actually move that a bit closer again because we better to have something closer up like that okay so here we have it now that's a little bit better so this red line represents the overall length of the building that we want and it has a corresponding red line drawn down here from T one to T zero so the second method of scaling is by reference the first method I showed you was by typing in the 0.01 the second method is by referencing so up here this would be called a reference line so I'll show you this unlike your twice just so you can see the keystrokes involved because it's important to get them in the correct order so again to start off the scale command s C and enter the command line is saying select the objects so you can just draw a selection box over the bit you're interested in and then press Enter specify the base point this time I'm going to select the end of the red line up here that's my base point now what we did the last time was we typed in a number down here so specify the scale factor we typed in 0.01 this time however I want to scale by reference so you can either do a left click on the word reference there or you can press the letter R on your keyboard and press Enter now it's saying specify the reference length so what you need to do is specify the length do you want to alter so do a click on the left hand edge of that red line all the way over here and do a click on the right hand edge of it you can see a kind of coarse grain out and now on your command line it says specify a new length or do it by points so I'm going to do it by points if I click on the word points there what I need to do now is come up to the line and do a left click on the left hand side of it and do a left click on the right hand side of it and you can probably see what's happened on the bottom of the screen there now the red line that I use as my control reference line down here has expanded it has grown and it's now three thirty nine thousand five hundred units long so it's matching what we have up here I'm just going to undo that last step so that you can see me doing it again okay so here we have the drawing it's not exactly right the overall dimension but it's close because we scaled by a factor of 0.01 already so here's how we scale using reference again s-see and enter select the part of the drawing you're interested in and press Enter specify a base point I'm going to click in the left hand edge of that red line I'm now going to specify the scale factor using reference so I'll click on the word reference you have to select a reference line first so left-click on the end left hand edge of that red line left-click on the right hand edge of that red line then come down to your command and select points so click then left-click on your read on your the line that's the right length left-click on the other end of it and the red line everything this was selected down here has been resized to match that line now how you can double check that this has worked absolutely correctly it's very simple come down here we know from the PDF that the distance between t1 and t2 should be 5920 we do a linear dimension now well it's not exactly right I might have actually just possibly snapped onto something a little bit odd back there but it's certainly you know within an order of tolerance I would imagine 519 point 8 millimeters is as close as you're going to get five thousand nine hundred and twenty it's off by 0.13% point one seven of a millimeter which is probably something you're not going to be able to measure on the site anyhow I'll just probably one more let me just be a little bit more careful about how I snap onto here again we've got four three three four point five instead of four three three five okay so we're off by about a half a millimeter there I'm not entirely sure why it's off by than half a millimeter it should be it should be absolutely more precise than that but having said that we're fire closer to having it the right way at the right dimensions at this stage I'll just read one more at random just to see what were coming up with this one here is meant to be 1085 so if I checked from there make sure my object snaps are set for intersections and I've 1:08 3.6 okay so again I'm off by about one point four of a millimeter perhaps if I had turned my dimension style to have to show no decimal places it might actually improve that so if I go up here to my dimension styles and modify them and have a look for the precision and change that to no decimal places and go ok and close and if I just delete that dimension for a second and try putting it back in so we've got 108 for instead of 108 five and I really don't think you're going to get any better than that when with scaling a PDF remember this is not a drawing that was generated within AutoCAD itself it was draw it was brought in imported as a PDF so I mean you know you're gonna find a millimeter or so here and there which is going to be outside of what you would expect but for most cases that's going to be close enough and acceptable and certainly if you're in any doubt about whether those dimensions are accepted ly close or not you would need to speak to your client check with the engineer check with the architect certainly it's worth asking the question or you know if that's going to be a problem maybe the architect or the engineer could supply you with the DWG instead of having to use a PDF in the first place so coming from the PDF this is probably the best you're going to get so let's do one more here as a quick check okay so we're off by two millimeters there now I would argue that the overall length being correct is more important than a millimeter or two in between but that's a question to check with the architect or with the client

Channel: CAD and Stuff

Views: 183,268

Keywords: CAD, AutoCAD, scaling, reference, scale factor, scale, re-size, drawing

Id: e4fTHkhZzqs

Length: 12min 29sec (749 seconds)

Published: Tue Jun 07 2016