Exactly what I needed! You just saved me several hours.
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Please add this. You have more than enough room on the app interface since we already have to scroll the selection bar over for the laser pointer when in portrait mode anyways. This is a CRITICAL feature. The "snap to shape" tool is simply not enough. A ruler is necessary when needing to draw a dotted line (although a built in dotted line option would be great too), to erase in a straight line, to measure out specific and proportional line lengths, etc. You can add a built in protractor to the ruler as well to get exact angles for subjects like trigonometry and physics. It honestly appalls me that this feature is not built in yet, it has over 4,000 votes (more if you add up all of the different posts about this feature besides just this thread), and has been asked for since 2015. This is such a simple feature to incorporate, please add. Please look to the built in ruler in the apple notes app for inspiration. It is perfect. I have posted a picture for your convenience.

It’s so hard to make a scale model or accurate blueprint. Something that tells me the measurements on the page is using. It may be a small thing for some but it’s very frustrating for others.

A set square and a compass would be even fantastic for this application!!!

Would be an awesome new feature! Missing this for my Smith Charts

Thanks for sharing. I found a lot of interesting information here. https://www.indigocard.org/

yes, please: *DISTANCES* and *ANGLES* [incl. hack]
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<-- my current workaround: i created a sticker collection and containing a triangle ruler (png with transparent background) from the web. it can be shifted, rotated and scaled and allows for manual measurements and construction
--> could/should be more advanced from within the app. a tool that allows snapping, entering parameters, etc., both for analysis and construction

Please add a ruler, would be super useful for making scale drawings for my engineering notes, and lines at a specific angle. Thanks very much

Please add a ruler, or even better a triangle ruler. It will be necessary for my students to draw engineering diagrams or force diagrams. We, currently, need to get back to analog paper drawings... this can´t be your intention.

My hands are pretty shaky, a ruler would solve the issue of uneven straight lines immediately. Im shocked this hasn't been added already.

We *need* the triangle ruler!

Please add this feature! The shape recognition is incredibly useful but it is not capable of some of the features of a ruler. The ability to draw perfectly parallel lines, dashed lines, and to align different parts of a sketch are all only accomplished with a ruler over the automatic shape feature. Adding a protractor, compass, French curves, triangles, and all sorts of hand drafting tools would make this app absolutely fantastic!!!

3-hole punch guides, I’d like to be able to print pages and store them in my binder.

Ein richtiges Geodreieck wäre ein Traum!

Yes a ruler, and an ability to measure distance between different points of a PDF.

It’s been 6 years, why doesn’t it have this feature? And dotted line .it’s been 8years

I'm still waiting! This would be great. Basically a must if I want to use this for engineering purposes. Would be nice if I could do this on my iPad.

Yes Please! and a protractor!

Some more Math tools for example Triangle ruler (there is no app coming up with that), dotted lines, Circles with center,...

this would be great to be able to write straight on paper without the grid. and for egr classes