My dual slope laser went out now I’m forced to use my single slope one in the meantime, problem is I’m working on a dual slope project. So the question is how to calculate the direction and slope needed to aim the single slope laser to accomplish a dual slope. The project has a -.5% grade on the x axis and a -.25% grade on the y. My rudimentary calculation has it aimed at 35* and a -.58% slope. Can someone please give me the correct formula for this. Thanks
Geometry wiz kid needed.
- Thread starter GrantB
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Gonna need some more details. I know Geometry, but I know dick about dual laser levels.
Picture would be +100
Picture would be +100
Ok, a rotary laser sends a laser beam perfectly level in 360 deg so no matter where you are around the laser it will be level, like a building slab. A single slope level allows you to manually adjust the laser beam up or down in one axis only, like setting the slope on a driveway going either up or down and the other axis remains level. Kinda like the slope on a swimming pool going from the shallow to the deep end, it slopes down but is level from left to right. A dual slope level allows you to not only adjust the level down going away from the instrument but you can also adjust it up or down from left to right.
The way it normally works with a dual slope level is you aim the laser (using sights on the laser just like iron sights on a gun) towards one slope, let’s say at 12 o’clock dead ahead and you manually force the laser to tilt down to the grade you want, so now it’s like you are looking down a hill but it’s still level left to right (this is single slope mode). Now with the second slope you want that hill lower on the left side and higher on the right. It’s like looking down a hill at an angle, you are sloping down and to the left at the same time.
I see your 2 and raise you a quarter...
Wait, what was the question?
I can’t read those numbers in the illustration.
The formula for slope is rise/run. Multiply by 100 to express as percent.
To find the angle use the arctan function on your calculator.
Example. 7 % slope rises 7 ft over 100 ft run.
Arctan (.07) is approximately 4 degrees
Use a trapezoidal section to calculate slope across the major diagonal for your case of unequal slope across 2 axes
The formula for slope is rise/run. Multiply by 100 to express as percent.
To find the angle use the arctan function on your calculator.
Example. 7 % slope rises 7 ft over 100 ft run.
Arctan (.07) is approximately 4 degrees
Use a trapezoidal section to calculate slope across the major diagonal for your case of unequal slope across 2 axes
Lets call your rectangle ABCD.
Place your level at vertex A.
Use pythagorean theorem to find slope AB and AD. You will create lines AB' and AD'
Created slope B'C' will be same as slope AD', use the same difference in elevation find C', draw AC'
OR
Use Pythagorean theorem to find hypotenuse of triangle ABC.
Use Pythagorean theorem to find slope AC'.
There are a couple other ways.
Place your level at vertex A.
Use pythagorean theorem to find slope AB and AD. You will create lines AB' and AD'
Created slope B'C' will be same as slope AD', use the same difference in elevation find C', draw AC'
OR
Use Pythagorean theorem to find hypotenuse of triangle ABC.
Use Pythagorean theorem to find slope AC'.
There are a couple other ways.
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Take the cross product of your plane edges. That's your normal vector, n
v = xy plane
then cos t = (n,v)/|n||v|
that gives you the "down" angle.
the angle in the x/y plane will be the arctan of grade x/grade y
v = xy plane
then cos t = (n,v)/|n||v|
that gives you the "down" angle.
the angle in the x/y plane will be the arctan of grade x/grade y
Glad you got it. I’ve used a laser level a ton for concrete work (seriously), but I’ve never done slopes with one. When I was working slopes we used a transit or a pea shooter and worked off of points that were shot in by our dreaded enemy-the engineers. So we never had any use for anything other than basic math off a lathe stake as a reference.
Have someone hold a pole on X axis and shoot a level line and mark. Repeated for Y, then adjust both on your rotator until both are aligned.
Or, use the bubble on top?
Or, use the bubble on top?
I was going to say 42. But that was more of an algebraic equation than some sort of wierd parallelogram..
Can mice even do geometry?
Sirhr
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