How do I sketch dimensions to a pyramid structure?

[chrisleckie]

Im looking to add dimensions to this structure. 

[etfrench]

Dimension type changes by moving the cursor in relation to the item being dimensioned.  Aligned dimensions are what you have drawn. You may want to use angle dimensions as well.  Are all of the lines in the same sketch or on the same plane?

[chrisleckie]

I understand how to use "sketch dimension" but because there are only 2 planes; the base and the one point at the top, I am not able to add dimensions to the 3 lines in between. These lines need to have precise lengths.

[etfrench]

 What is the purpose of the dimensions? Do you want to be able to change their values in order to change a body or do you just need to verify the exact length?  Any dimensions you add will over-constrain the model.

There are several different ways that you could use to locate the point.  One would be to create a plane at 90 degrees to the center of the base triangle and locate the point on that plane using a dimension.  Another would be to use a plane between two lines on the two of the vertical legs of the pyramid.

[chrisleckie]

I am trying to use this method to triangulate the point position. The base of the triangle will always stay the same but the point will change in my project. I have 3 measurements to work from  

[etfrench]

If it's only moving in the Z direction and only one of either Y or X, then a plane at 90 degrees to the base will handle it.   If it's moving in all three, then it's a problem

[HughesTooling · Accepted solution]

Here's a screencast that might help. File's attached.

Mark

[chrisleckie]

Thank you so much for taking the time to do this! Ive been hunting for the answer for over a week now. This will allow me to 3d print a part that I can then rigidly attach to a structure that I need to take measurements from. Using the triangulation method I can now plot points in 3d space that I would otherwise never be able to do!  

[Anonymous]

Another way of triangulation (without 3d-sketching) is to construct 3 spheres on each corner of base triangle, intersect them, it will give you 2 points (above and below of base triangle), any of which is your 4-th vertex of the pyramid.