New polyline at relative angle

[Simon_GustafssonC6JJB]

Hello! I'm quite new to CAD and I have a question. I have a polyline running at a certain angle. If I want to create a new polyline at one of its endpoints, or add a vertex, either is fine, at a angle relative to the polyline, how do I do that more easily? Using f10 I can snap to angles but they are relative to the coordinate system, not the original polyline. Using the extend reference line I can calculate what angle is 180 degrees relative to the polyline and calculate my wanted angle from there but it seems needlessly complicated. 

See image below. How do I create this 90 degree angle more easily? 

Thank you!

[Pointdump]

Hi Simon,
Welcome to the Autodesk Forums.
You can use Create Line by Deflection.
Dave

[AllenJessup]

Create Line by Angle Distance could work too. Depending on what information you have. In the image @Pointdump posted. You'll notice at the bottom it shows 'DD. That's  a Transparent command and can be called within another command. So you could start the Polyline Command and then enter 'DD for deflection or 'AD for the angle.

[Simon_GustafssonC6JJB]

Hello and thank you for your replies. In both 'DD and 'AD it seems I'm unable to specify the exact angle I want, I have to select it using the cursor? This is how the input looks like for me

I can only input the coordinate of a point, not the angle. Also, can I change the unit of the angle here? If I enter units, my units are set to degrees, not grads.

Thank you!

[Pointdump]

Simon,
You need to use Grad units for angle? You'll set that in Drawing Settings >> Ambient Settings >> Angle.
I tried just now to Create Line by Deflection, and I can't get it to work. I'll nose around and see what I'm missing.
Dave

[Pointdump · Accepted solution]

Simon,
OK, I see now how >>>Line by Deflection<<< works. You can enter the angle either in the command line or use Dynamic Input.
Dave

[Simon_GustafssonC6JJB]

Thanks Dave, that did the trick!