topic Re: How do I keep my AC models precise??? in Modeling

How do I keep my AC models precise???

Anonymous — Fri, 06 Nov 2009 16:48:41 GMT

Hi everybody,
I've been using AC12 for over a year now, and still wonder what's the matter with my snap/guidelines/general input settings... I usually work with the Standard AC12 settings.
No matter what I do or how much time I spend trying to get a precise model, eventually I always discover errors! Lines that were supposed to be parallel, but are't, angles that are close to 90°, but not really...

Anyway, my point is: I've used AutoCAD (the Evil!) for over 10 years, and my models/drawings have always been precise. No eyeballing, good snap settings, and I all the precision I want.

Then I switched to AC12. Great! BIM, wow! But precise? I'd be more accurate with a pencil and a broken wrist! I just spent an afternoon trying to fix a preliminary design model, and after a few hours I've decided I'd better re-do the whole thing, otherwise I'll be dragging around these f***ing (foxing) model errors until the end of the construction site!!!

Is there an effective way maintain an acceptable precision level in ArchiCAD???

Thanks!

Enrico

...or do I have to buy a plug-in for that??

Re: How do I keep my AC models precise???

Fabrizio Diodati — Fri, 06 Nov 2009 16:56:41 GMT

mmmmm...

Just before to leave the office to enjoy this week end at home and without any intention to be "polemic"...

Sometime (or often?) is not the tool but the "hand" using the tool that is doing something of wrong.

and now I feel myself like a wise Chinese old man

Friendly
Fabrizio

P.S. This time... at least this time (!) no need to buy a plug-in for that!!!

Re: How do I keep my AC models precise???

Erika Epstein — Fri, 06 Nov 2009 17:03:54 GMT

Enrico wrote:
what's the matter with my snap/guidelines/general input settings

Don't use the snap/guidelines. ALWAYS type in dimensions for accuracy. Hold down the shift key for precise alignment and angles. Other than the relative geometry buttons such as parallel or perpendicular , I find the guidelines take longer than using your non-mouse hand for the shift key and or with the r or a keys takes longer and leads to easily to inaccuracies.

Lots of discussion about this topic here along with heated advocates for each side. Ultimately if your method does not give you the accuracy you need, you should not use it.

Re: How do I keep my AC models precise???

Dwight — Fri, 06 Nov 2009 19:03:02 GMT

Slow down a little.

Re: How do I keep my AC models precise???

Karl Ottenstein — Fri, 06 Nov 2009 20:40:06 GMT

To repeat something else said often: never read numbers in the Tracker or Coordinate Box and simply click. What you see is not what will be. Always enter the numbers. This differs tremendously from Revit where if you see 20 meters in the Revit autodimension pop-up thingy, and click, then you indeed have exactly 20 meters.

Karl

Re: How do I keep my AC models precise???

Anonymous — Fri, 06 Nov 2009 22:16:37 GMT

Sorry I thought this was an archicad forum. why are you talking about revit?

go into grids & backgrounds & set the gridsnap/ nudge to an increment you will be happy with. ie 50mm or 2"

that way when you draw a wall or whatever it will draw to those increments instead of absolute coordinates. similar to revit.

nb. grid snap must be turned on.

you can also do the same with the construction grid.

this allows fast & accurate drawing

Re: How do I keep my AC models precise???

Anonymous — Fri, 06 Nov 2009 22:23:20 GMT

ps.

you must hold down shift to do this.

& guide lines dont seem to work when this function is on.

s is the shortcut key to toggle snapgrid on or off. which allows you to use the best of both the guidelines & snaps.

NEVER listen to people to tell you NEVER to do anything!!!!

Re: How do I keep my AC models precise???

Anonymous — Sat, 07 Nov 2009 03:24:54 GMT

This problem has been mentioned before a few times. Some people swear blind that ArchiCAD is inaccurate, while others have never had a problem!

Perhaps it might be helpful for those who are having the problems to describe the technique they use for creating geometry, and what settings and guides they have turned on. Maybe there is a common theme?

Personally, I always use the temporary guide lines in conjunction with the Tracker for drawing most things. I simply click once to start drawing, hover over the guide line that is created so it snaps to it, type the distance I want it to be, then hit return. I don't use the co-ordinates palette as some people recommend. I never use the grid either. I have never found I have any problems with the accuracy of the geometry produced.

Re: How do I keep my AC models precise???

Anonymous — Sat, 07 Nov 2009 06:48:41 GMT

There are two things I want to add in the discussion.
First of all, AC works with a lot of decimals, but which are not visible in your tracker. You can have more decimals visible than standard. Go to Options > Project Preferences > Working Units & Levels.

Secondly, you can set the accuracy of your snap with the cursor snap range:
Options > Work Environment > Mouse Constraints & Methods.

Re: How do I keep my AC models precise???

KeesW — Sat, 07 Nov 2009 12:27:22 GMT

You are right - it has been mentioned before (at least by me). I have found that Archicad objects are sometimes out by a fraction of a degree - so close to being right that one doesn't see it. Using the shift key doesn't help because this can be out by that same distance. I don't know what causes it but hope that it's been fixed for AC13.

How does one know it is out? The co-ordinates will tell you. Something else to remember!

Re: How do I keep my AC models precise???

Erika Epstein — Sat, 07 Nov 2009 23:34:12 GMT

It is not just using the shift key but in conjunction with r,a x or y and typing in accurate dimensions.

Re: How do I keep my AC models precise???

KeesW — Mon, 09 Nov 2009 01:49:02 GMT

I am sorry but I don't agree with Erika (in this instance only!). We don't always know what our dimensions are at the design stage - when still messing with shapes and layouts. I expect the shift key to give me horizontal and vertical defaults unless I have set them differently. Sometimes they don't - and this should not happen.

Re: How do I keep my AC models precise???

Dwight — Mon, 09 Nov 2009 02:11:36 GMT

There used to be a problem with a temporary constraint set using the perpendicular/parallel command. If this deviated from the axes by only a degree or two, you could inadvertently constrain to the wrong line. That was trouble!

I can't replicate this problem in 13......

As far as accuracy goes, I have just imported a Sketchup model. Krikey!!!
How does a thing get off true by .59 of a degree?