prax3des Posted June 19, 2018 Share Posted June 19, 2018 Hi, I have the following issue. I have a Point (A) that can be moved by Line 1 and Line 2 I have a Point (B) that can be moved only by Line 3 I have a Point C that can be moved only by Line 4 The lengths LC (25) and LD (15) form 40 which is a length to be respected. The length LA is variable. How can it be done to align Points (A), (B) and © so that they respect the comments? I give examples of how the cases of solution should be. Thank you. Problem.dwg Quote Link to comment Share on other sites More sharing options...
eldon Posted June 19, 2018 Share Posted June 19, 2018 You have to decide which point is to be fixed - A, B or C? Because fixing any one of them decides the positions of the other two. Have you tried using constraints? Quote Link to comment Share on other sites More sharing options...
prax3des Posted June 19, 2018 Author Share Posted June 19, 2018 No, that is the problem. Point (A) can be aligned with Line 1 or Line 2 Point (B) Aligned with Line 3 Point © Aligned with Line 4 Therefore if Point (A) is at the midpoint of Line 1, if Point (B) aligned with Line 3 and Point © aligned with Line 4, we would know the Length of LA. Is very difficult for me:( Quote Link to comment Share on other sites More sharing options...
eldon Posted June 19, 2018 Share Posted June 19, 2018 There is no single solution as you have already shown, therefore to get one answer you MUST fix one point. Or do you want a general equation to satisfy conditions? That is perhaps beyond the scope of AutoCAD, unless you go parametric. Quote Link to comment Share on other sites More sharing options...
eldon Posted June 20, 2018 Share Posted June 20, 2018 This picture shows the range of solutions possible. I have drawn the extreme positions and some intermediate ones. So for each particular value of one of the points (A, B or C) there is a unique value for the others. Quote Link to comment Share on other sites More sharing options...
prax3des Posted June 20, 2018 Author Share Posted June 20, 2018 correct !! Therefore I look for the method that marking a point, for example (A) at a distance X, Y of Line 1 and Line 2 would give me as solution the points B and C Quote Link to comment Share on other sites More sharing options...
eldon Posted June 20, 2018 Share Posted June 20, 2018 So you are fixing point A. As I said in my first response, use constraints. That would seem to be the solution unless you go for trial and error! Quote Link to comment Share on other sites More sharing options...
rkent Posted June 20, 2018 Share Posted June 20, 2018 (edited) No, that is the problem.Point (A) can be aligned with Line 1 or Line 2 Point (B) Aligned with Line 3 Point © Aligned with Line 4 Therefore if Point (A) is at the midpoint of Line 1, if Point (B) aligned with Line 3 and Point © aligned with Line 4, we would know the Length of LA. Is very difficult for me:( From your example it look like the diagonal line is required to be perpendicular to line B C. Using constraints you can set this up so if you move A, B, or C they will adjust to keep your parameters in check. Lines 1 and 4 will be set to vertical and Fixed in place. Lines 2 and 3 will be set to horizontal and Fixed in place. Point A would be COINCIDENT to line 1 (or COINCIDENT to line 2 in another setup) Point B would be COINCIDENT to line 3 Point C would be COINCIDENT to line 4 Line C-D would have a dimconstraint to 15 (and again to 40 in another setup) Line B-D would have a dimconstraint to 40 (and again to 15 in another setup) Now you can grab the grip of the end points of line A-D or B-C and adjust. You will have to end up with 4 different solutions with the various parameters. Edited June 20, 2018 by rkent coincident not collinear Quote Link to comment Share on other sites More sharing options...
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