iDraw - grids and things

I talked last week about the usefulness of layers in iDraw, and made passing reference to a grid. I’d like to talk a bit more about techniques for measuring and positioning in drawings.

Pretty much any drawing software will have some sort of a grid feature. Like drawing on graph paper, a grid gives you a sense of scale. In software there is also a “Snap to Grid” feature which means as you draw, edges, vertices, end points etc. will always “snap” to the nearest grid lines. This makes it very easy to ensure, for example, that the line you’re drawing is exactly 3.5cm long, rather than just approximately. If you’ve ever tried positioning something on screen using a mouse you’ll know how hard it is to be precise, so the grid makes things easy.

The grid in iDraw allows you to set the spacing between lines, and it is also a two-level grid with thicker lines at intervals that you can also set. For my battleship project, I’ve chosen a grid size to match my drawing scale, so that each big square is 10’ across with 1’ subdivisions. Yes, I was taught metric at school but I still think in feet & inches.

The grid lines are very faint here, but if you click on the image you'll see a larger version. As I mentioned last week, I usually supplement iDraw’s grid with extra placement lines of my own. In this image, a detail of the battleship’s main armament, there is a red line running down the center. I typically use some combination of center lines, boundary lines showing the outside edge, and additional grid lines at suitable intervals, such as a 100’ scale. It depends on the project, I only add what I find useful. These lines go into their own drawing layer so they are easy to hide, and they don’t get in the way and can’t be accidentally selected or moved.

iDraw has another really neat positioning feature. Suppose I want to make a second copy of this object and place it directly underneath the first. I copy and paste as normal...

Then as I move it around, iDraw flashes up vertical and horizontal lines as the object I’m moving comes into alignment with other objects on the page. This tells me when I’m lined up, without having to measure against the grid.

This feature is very useful, though it does have drawbacks. As you move something around these lines flash on and off, and sometimes it’s hard to work out exactly what object it’s aligning to, which might be well off the edge of the screen.

Also I’ve found iDraw will sometimes snap to some alignment it’s detected instead of snapping to the grid. I often look at something and think it looks a little off. I zoom in and find it’s ignored the grid. It’s easy to correct things when you’re zoomed in enough so that the software can distinguish between the competing grid/alignment lines, but the trick is to spot the error in the first place. I’m now in the habit of zooming in periodically to double-check sizes and positioning. I guess that’s the price you pay for making things mostly easy :)

One more thing iDraw is not so good at, especially when it comes to line drawings like this. If you select a collection of lines, squares, boxes etc. it can be tricky to pick them up with the mouse pointer. You have to position the pointer very close to one of the lines, or it thinks you’re making a new selection and will “drop” everything you so carefully selected. This is especially true when you’re zoomed out a long way like in this view...

Individual lines here are hard to see, let alone grab, but in this project I often have details (such as stairwells or elevator shafts) on one deck that I want to copy and paste to the same locations on other decks. To make this easier, you’ll notice some red triangles down the left-hand edge.. If I select a triangle along with the details I want to copy or move, this does two things: it gives me something easier to grab when zoomed further out, and, because I draw those triangles in the angle of my main grid lines, it gives me a reference point to ensure things get properly positioned again. All I have to do is ensure the triangle ends up back in its “home corner”.