Metric project

[rbanker]

I am getting ready to begin a metric project in Civil 3d 2008. I'm aware of all the metric templates and tool palettes that are available...

The trouble is, I have never in my life worked with metric units. Can anyone give any advice, tips, or cautions that would be helpful?

Thanks for any guidance y'all can give!

Rich

[jaberwok]

Have a good long think about your basic unit - metre, centimetre or millimetre.

[tedg]

In my limited experience, the base metric unit for civil work is a meter.
So in this case you'd set up your drawings in (metric) decimal units where one unit is a meter (M).

But I don't do much civil work and a little metric work. I do mostly Architectural and Structural drafting, and when we need to use metric we use millimeters (mm) as our base units.

That's my two cents, good luck :beer:.

[dgorsman]

Everything is in "tens", naturally. Depending on what is being drawn, your units will be either meters or millimeters, or maybe kilometers if a large enough area is covered. The units will also control precision - meters are typically three decimals (to the millimeter) and millimeters have no decimals unless doing a hard conversion from an object created to imperial size. Mind your individual components, you may end up requiring imperial-sized objects in a metric-sized drawing. Have a look at some common sizes you are used to working with and convert them to metric values so you have an idea of what numbers look too large or too small.

[s_morgan_b]

We typically work in metres for our projects (being in Canada and all) but, much of the time, architectural material will come in in inches or feet.

Three decimal places for your units.

Just make sure you don't draw in metric and leave the ddunits/insunits in "feet" - that makes a horrible mess.

If you have premade blocks, you will have to recalculate your scale factor for insertion.

[irneb]

Your premade blocks might come in correctly if you've set them & the current drawin up correctly: type UNITS at the command prompt in the block, set everything in the dialog to Inches (or whatever they're drawn in). Likewise type UNITS in the metric drawing, change everything to meters (or which ever you decide). AutoCAD should now handle scaling automatically when inserting the block.

Some other problems to look out for are Hatching & Linetype scaling. This should be sorted if you're starting from scratch and using the metric templates. But you may find that hatches / linetypes need a different scale factor if you're xreffing an old imperial file into the metric file. The major difference between IMPERIAL & METRIC is the MEASUREMENT system variable which is set to 0 for imperial and 1 for metric. This basically tells AutoCAD to use the ACAD.PAT and ACAD.LIN for imperial hatches & linetypes, or the ACADISO.PAT and ACADISO.LIN for metric hatches & linetypes.

The imperial versions are designed to look correct at a scale factor of 1.0 if working in inches and your drawing scale is 1"=1". The metric versions are for millimeters at scale of 1:1.

As stated xreffing may cause havoc with these. There's no easy way of getting around it. Convert each base file to the current system before you xref it into the new file. Reload all linetypes and re-edit all hatches. Very tedious I know!!!