How to Draw a Line with Slope

Edip Ahmet TAŞKIN said:

I expect that it calculates 1300 - (1300*0.5) How can it be calculated from the first elevation?

First, I am not sure what role to 40^ plays in you second point, but that does not factor into the 5% slope.

AccuDraw normally follows the points as they are placed and rotate to the element. So when you place your initial point at 1000, 1000, 1300 the Accudraw compass is at that location and is rotated to the view and it is on the 1300 Z plane.

Entering your second point you will enter 40 meters & 40^ in the polar coordinate. Since you are on the 1300 Z plane you will not enter 1300 x 5 to calculate your next point. You want a slope 5% from the 1300 elevation. I converted the 1300 meters to 4,265.09'. A 5% slope over 40 meters (131.20') will be 131.20 x 0.05 = 6.56'. So your value to enter at this point is (131.20 + 6.56 or 131.20 - 6.56 depending on whether you need a positive or negative slope). So your Z value to enter into AccuDraw is either 41.99 M (137.76) for positive or -37.99 M (124.64) for negative. Once placed check the elevation which should be either 1341.99 or 1262.01.

Hopefully all my math is correct. Your original formula to calculate the 5% slope was assuming AccuDraw was at elevation Zero.

Edip Ahmet TAŞKIN said:

I expect that it calculates 1300 - (1300*0.5) How can it be calculated from the first elevation?

First, I am not sure what role to 40^ plays in you second point, but that does not factor into the 5% slope.

AccuDraw normally follows the points as they are placed and rotate to the element. So when you place your initial point at 1000, 1000, 1300 the Accudraw compass is at that location and is rotated to the view and it is on the 1300 Z plane.

Entering your second point you will enter 40 meters & 40^ in the polar coordinate. Since you are on the 1300 Z plane you will not enter 1300 x 5 to calculate your next point. You want a slope 5% from the 1300 elevation. I converted the 1300 meters to 4,265.09'. A 5% slope over 40 meters (131.20') will be 131.20 x 0.05 = 6.56'. So your value to enter at this point is (131.20 + 6.56 or 131.20 - 6.56 depending on whether you need a positive or negative slope). So your Z value to enter into AccuDraw is either 41.99 M (137.76) for positive or -37.99 M (124.64) for negative. Once placed check the elevation which should be either 1341.99 or 1262.01.

Hopefully all my math is correct. Your original formula to calculate the 5% slope was assuming AccuDraw was at elevation Zero.

mwlong said:

Once placed check the elevation which should be either 1341.99 or 1262.01.

1300+(40*0.05) = 1302m

1300-(40*0.05) = 1298m

Thanks for checking the math. I did not double check it. I was also converting to imperial units.

Hahaha I did a big mistake about Z x Slope. I calculated it manually with distance x slope but typed wrong in my question. Sorry :) 

I am using an application called Terra Model for terrain modeling. There is a command for creating sloped lines and a few other handy tools as well.

Thanks for your suggestion.