AutoCADBeginner Posted February 24, 2014 Share Posted February 24, 2014 Hi there, We are currently working on various exercises from the textbook: AutoCAD A Problem Solving Approach. When it comes to Problem Solving Exercise 1 (Figure 3-57) on page 3-32, we are very confused. Is there any way anyone could provide any guidance on how to successfully complete this exercise? Any help would be greatly appreciated! Thanks! Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 (edited) Not everyone here may have a copy of the book. It might help if you provide us with more detail. An image perhaps? BTW...We are talking about the AutoCAD 2014 edition right? That's not the exercise with the arc is it? Edited February 24, 2014 by ReMark Quote Link to comment Share on other sites More sharing options...
eldon Posted February 24, 2014 Share Posted February 24, 2014 Seek and ye shall find Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 Thanks eldon. I vaguely remembered it but wasn't 100% sure. Well first off I see there is no radius given for the two arcs on the left hand side. Quote Link to comment Share on other sites More sharing options...
eldon Posted February 24, 2014 Share Posted February 24, 2014 Wouldn't that be 0.48 radius given by a horizontal dimension, rather than a conventional Radius dimension ? But my image is snipped from Google, and the figures are not of the best Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 That's what I'd assume but it should be stated. Have you tried the exercise yet? Do you agree that in theory the arcs on the left should be tangent to the vertical line .98 and 1.83 lines? Do you also agree that in theory the arc on the right should also be tangent to both of the 1.83 lines? Quote Link to comment Share on other sites More sharing options...
eldon Posted February 24, 2014 Share Posted February 24, 2014 I have tried the exercise and can say that the dimensions are not compatible with an even geometric shape. I cheated and used fillet among other things Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 I cheated and used Circle with the TTR option. My arcs have a radius of .48 and the vertical line on the left has a length of .98 and both my angled lines are 13 degrees off the horizontal. Unfortunately they are not 1.83 units in length. I also get a different angle on the right and a different distance than 0.39 as well. I think there is something amiss with Shammy's sketch. Quote Link to comment Share on other sites More sharing options...
eldon Posted February 24, 2014 Share Posted February 24, 2014 I think that the dimensions are arbitrary!!!!! For example, the angle at the centre of the right hand arc should be (180 -(2x13))=154, not as shown 145. Perhaps part of the problem solving is to say the the dimensions given will not produce the desired figure. Quote Link to comment Share on other sites More sharing options...
JD Mather Posted February 24, 2014 Share Posted February 24, 2014 There are several errors in the dimensions (especially if you assume tangency between the arcs and the lines). My guess is the 145° is transposed digits as eldon suggested. My guess is that the .39 is incorrect (I get .382 if I make the horizontal dimension .48). Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 I guess the student is left to pick what they want to hold and make the remainder fit. And that teaches them what? Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 My first attempt. I'm working on a second which is already different! Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 My second attempt. Should I try a third? Quote Link to comment Share on other sites More sharing options...
eldon Posted February 24, 2014 Share Posted February 24, 2014 Perhaps this is a lesson that one should not believe everything that one sees in print Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 Maybe the example works in an alternate universe? Quote Link to comment Share on other sites More sharing options...
JD Mather Posted February 24, 2014 Share Posted February 24, 2014 Oops, I completely missed the 1.83 dimension. There are too many dimensions if one assumes tangency and then it becomes a question of which ones to ignore and which ones to use as controlling dimensions. It might make a good lesson in geometric construction vs trig hand-calc approximations. If there is a geometric construction method that avoids hand-calcs, that is what I use. Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 What would you advise the student(s) to do? Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 (edited) My third and last attempt. Pick your poison. The book should be renamed...A Problem Creating Exercise! LoL Edited February 24, 2014 by ReMark Quote Link to comment Share on other sites More sharing options...
eldon Posted February 24, 2014 Share Posted February 24, 2014 It might be that the image I took off the web is deliberately wrong, to distinguish from those who had actually bought the book! Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 24, 2014 Share Posted February 24, 2014 (edited) Notice the OP never came back. So much for being interested in getting some help. Oh well, on to more interesting problems. Ring me up if the OP returns. Edited February 27, 2014 by ReMark Yes, AutoCADBegineer did show up. Quote Link to comment Share on other sites More sharing options...
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