Hi isaac, well definitely it saves a lot of steps using the Box command to make a Box rather than manual line drawing... There is also a "3pt" variant of that similar to the 3pt rectangle (for more free orientation), and you also can easily enter any value for width, height, or extrusion - those options will show up in the upper-right corner of the window. Just type in "24" where you want a width, height, or extrusion of 24 units and you'll have it.

But you can still do what you are describing with just the polyline tool in MoI plus construction lines, here is a demonstration of that:




Here is a walkthrough:

I placed the first 2 polyline points just at arbitrary locations on the x/y plane to make one edge of the box.

Now for the 3rd point, you can see that moving along the z-axis will let you snap in that direction - this is not exactly a construction line yet - this is "Straight Snap", if you don't see this part it means you probably have Straight Snap turned off in the bottom toolbar, it must be turned on (highlighted in orange) to get this kind of axis snapping from the base point when drawing lines.

Now you wanted that 3rd point to be 24 units above the plane, so for that you can use distance constraint - type "24" and hit enter (or click on the "d" text box in the bottom toolbar to use the little pop-up panel with the mouse), now the distance from the previous point is locked to 24 units. Now click to place the point 24 units up in z.

For the 4th point, you want it to be an "inference" above the initial one, for this one you will need to create a construction line. Basically any time you would want an "inference", that is when you will create a cline. To do this, move your mouse to that original point and click and drag and use straight snap in z to make a z construction line, snap perp to it, and then close the polyline.


So to make the vertical rectangle, just type in 24<enter> when you want a height of 24, and just drag out a cline where you want the inference, and that's it...


Then if you want to continue drawing the box, each spot where you want an inference, drag out a construction line, here I did 3 perpendicular ones to make a kind of scaffolding along each inference point that you would want, to set them all up for drawing it.


Just every place where you would want to make an "inference", drag out a construction line there and you should be able to get the exact same behavior...

Does none of this seem to work for you? I mean there is a lot of stuff in there for drawing in the 3D view, snapping in Z, etc... just like you are asking about.


I would recommend zooming in a bit so the screen is larger than in my screencap here, I have done the drawing here in a kind of small area on the screen to make the video a smaller download size.


Also again just to be clear, I would also recommend using Box 3pt to do this with far less messing around for this particular shape, this is just to show you how to do the same thing by direct drawing in the 3D view using clines.

- Michael