Engineering drawings and aids for drawing with the mouse

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Engineering drawings and aids for drawing with the mouse

Ajohn
Just on engineering drawing aspects.

Needing to place say several holes in a circle at specified angles is a pretty common. There doesn't seem to be any easy way to do this or draw gears and other things like that. A start would be a facility to lay out witness lines in that fashion. That would allow hole centres to be marked out and then drawn individually. Gears are usually taken care of with a dedicated facility but really 2 concentric circles will do.

There is an exercise at the end of a tutorial showing an engineering type part. Normally parts like that would have a rad or chamfer on all edges. This can be done by drawing witness lines to position the rads and the joining them up but a facility to do this would save time.

Drawing with a mouse
I have tried several packages over too many years but all seem to be weak in this area despite all of the graphics shown on the screen. The general attitude seems to be use the command line if "proper" drawings are needed.  More suitable for people who use it a lot rather than casual use. In the past I have tried using small snap distances but it never works out well. Not even really adequate for making sure for instance that some kitchen units would actually fit in a room and even worse for engineering drawings where distances between parts can be really tiny.

As a for instance I opened up LibreCad and wanted to draw a circle 94.5mm dia. Easy with the command line but a box on the display could tell me what the rad or diameter is as I move the mouse. Same with lines, it could tell me the length. A sort of measurement facility that used the same box could tell me how much I have moved the mouse by. These could all default to x or y directions and keyboard modifiers used to change that. Use of the left control, shift, alt and windows key can be used to do that. The ones on the left usually but some would want them on the right.

The next thing I wanted to do was add in this case 120 radial witness lines to the circle  so I gave up. I might want to add them using an angle instead.

This might sound crazy but zoom makes this sort of thing pretty easy with one proviso. I make a lot of use of a photo app called Fotoxx and this often means using high magnifications. As I move close to the edge of the screen I can use the mouse to bring more into view.This usually happens by simple pressing the mouse button and moving it nearer to the edge of the view. The same could be done while measuring a distance or drawing lines or circles etc.

I noticed a comment about lines not really joining up even though they may look like they do. The GIMP manages to offer users the opportunity to snap to nearby points if they wish as the mouse move close to them. Think it's on paths but it may be used elsewhere. It should be possible to use the same technique to snap to anything that has been drawn or some part of it.

I didn't notice anything to allow me to draw witness lines. This can be done on another layer. They are just faint lines used as a preliminary to drawing something. Using pencil and paper they would probably be rubbed out at some point. Rather than having to do this manually an icon could be used to switch between these and real drawing lines.

Fotoxx has another useful feature that is likely to be of use in a drawing package. Most actions need the left mouse button holding down. A right click undoes what ever has just been done with the left key pressed down. This could be a modifier mouse click or what ever.

I suppose this will all fall on deaf ears as many users will be using it a lot at speed using commands. Casual users may feel otherwise. One of the big problems with many cad packages is learning to use them well or even effectively. It can take a long long time. Also if the command line has to be used why bother with all of the icons if they can't do a decent job.

I noticed a comment about messy menu's. Seems ok to me and people will soon get used to where things are. Wish that was true of the GIMP at times. One thing I often miss though is menu's which also show the appropriate short cut key as well as the description. That way new users can pick them up when they feel that they need to.

Sorry to mention other types of graphical packages but the needs of those are similar in several areas and often there is a need for them to do very fine work, screen wise at very high magnifications.

 Should add that I spent several years on a pencil and paper drawing board some time ago so do know what is needed to draft things. To be honest speed wise except in instance where common components etc are used and with such tasks as splitting up a circle in odd divisions it's far quicker to simple draw things that way rather than trying to pick up cad packages. It's pretty common for people who use them, even 3d packages to make use of witness lines.

John
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