Block Scaling too Large

One of my colleagues reminded me of an age old problem I have encountered several times and never got to the bottom of, when inserting a block it scales to a strange size and doesn’t fit to the page.

This turns out to be yet another setting between the “American Imperial” measurement system and the “International ISO Metric” measurement that exists in AutoCAD.

It turns out that changing MEASUREMENT setting to 1 (metric), from the default of 0 (imperial) only changes the way hatches and linetypes scale and not the inherent way the drawing works. The underlying unit scale of the drawing is governed by other setting. So old drawings created when out-of-the-box AutoCAD defaulted to imperial might still have all the old settings.

DWGUNITS command line options
DWGUNITS command line options

The option in question is DWGUNITS. It appears that the default is 1, which is inches. This is why a block drawn in a drawing using DWGUNITS of inches is inserted into a drawing set to mm scales to a differing scale!

As an aside DWGUNITS also sets linear display precision, which is also set by LUPREC.

The options after DWGUNITS is typed appear in a pop-up command line box for easier reading, they are as follows:

Unit for length:
This is the overriding base setting between metric an imperial, here we note that the original setting was 1 for the block template and we changed it to 3, which is the system we use in the office.

Linear display format:
This changes the output reading for items like DISTANCE from 2000.000(decimal) say to 2.000E+03 (scientific). I find the decimal easier to read so we will select 2 here.

Linear display precision:
This governs the number of decimal points in the output reading for items like DISTANCE. 0 gives a measurement of 2000, 1 results in 2000.0 etc. I tend to leave this at 3, but this is personal preference. (LUPREC system variable also changes this setting, and is also found in the dialogue box after typing UNITS, found under menu –> FORMAT –> UNITS).

Scale objects from other drawings upon insert:
This is the one that makes the drawings scale from one unit set to another. I have left this as YES as it will highlight any other blocks and drawings that might not have been set to mm in the first option. Otherwise the block will be inserted without scaling and the error persists.

Match INSUNITS to drawing units?
INSUNITS is another option to scale BLOCKS on insert. It is best to say yes here so they do match, otherwise errors could occur!

Scale objects in current drawing to reflect change in units?
This one you need to say no to. The reason being is that you have drawn a line that is 2000 units long, and in this case before changing the DWGUNITS this would have been interpreted as 2000 inches. AutoCAD can scale the drawing (which is sometimes useful when say changing from a drawing that was actually drawn in inches to metric) however in this case you want to preserve the “2000 units” as 2000 and just change the unit type from inches to mm.

Then the drawing and block drawn in the drawing will be compatible with other drawings drawn in mm.

Please note that DWGUNITS and UNITS are completely different commands.

Please also note the DWGUNITS command is undocumented in AutoCAD both 2013 and 2014 help, it might be present in previous versions but probably need to go back many years to obtain anything!

Constrained

One of colleagues today noted that today he had annoying boxes. When I looked at his screen he had something like this.

Strange Boxes
Strange Boxes

These strange annoying boxes are constraints, part of AutoCAD’s parametric system, found under the Parametric Tab on the ribbon (strangely).

In order to use constraints you need to click the INFER constraints button on the bottom left of the status bar. This allows objects drawn in this mode to have the Parametric constraints. This button looks like this

Turn on Constraints
Turn on Constraints

Or this, depending on whether you use icons or not.

constraints01Once on you can draw your objects to be constrained. Here I have drawn a rectangle and a polyline. If I move the polyline the rectangle will deform as the polyline and the rectangle are linked or constrained together.

constraints04

constraints05

If you do not want this constrain feature on this object anymore you can click on the object and then delete constraints on the ribbon.

constraints06

Once removed the object returns to a plain old rectangle polyline.

constraints07

Remember to turn off the INFER constraints button before drawing anything else as all items drawn will have this parametric capability.

 

 

Rotating LT

One of my colleagues asked this morning how to easily rotate the view (and UCS) to help with drawing, now in full version of AutoCAD this is simplicity itself.

Rotate from Viewcube
Rotate from Viewcube

Just click on the arrows above the Viewcube to rotate the view and UCS simultaneously.

In AutoCAD LT this is more difficult, you can either use one of several command line methods, either using PLAN or UCS by object etc.

OR, this method seems to be easier (though it needs a little setting up). And here is how to do this.

Firstly, AutoCAD (LT) 2013 seems to come “out-of-the-box” with certain Panels turned off in the Ribbon. One of which is the UCS coordinate panel (why would they do this?) on View Tab.

Turn on coordinates panel.
Turn on coordinates panel.

Click on the View Tab and then right click anywhere on the panels below, then go to Show Panels, Coordinates. Now you have the coordinates panel which should have been there in the first place.

Secondly you need to make sure the view rotates with the UCS when you change the UCS. To do this click on the little arrow to bottom right of the Coordinates Panel, this brings up the UCS options box, Click “Update view to Plan when UCS is changed.” Click OK!

Enable Plan to Rotate with UCS
Enable Plan to Rotate with UCS

Now we are ready to go! (Phew!)

Rotate about the Z axis
Rotate about the Z axis

Click on the drop down menu which has Axes and a rotate arrow. Click on the Z icon and voila you can now rotate around the Z axis and the drawing will follow. The default selection is 90 degrees so hitting enter after clicking will rotate by 90 degrees.

So now its “one click and enter” to rotate the view and UCS in AutoCAD LT versus the “one click” in full version, hopefully a simpler method than all the command line options!