Reference Line location is not correct

[Steve Jepson]

In a composite wall I have included a vapor barrier for several reasons. It has the minimum default thickness which is 1/64". The reason it needs to have this minimum thickness is because of the graphics display errors you get if you try to set this thickness to 0".

The problem with the reference line in a wall like this is that the reference line does not show up in the correct place relative the material thicknesses that have been assigned to the wall.

For example, 3/4" + 1/2" + 1/64" = 1 17/64"

I can not get the reference line in that location so it will match graphically with the materials. This causes several kinds of problems, some of which are important.

http://screencast.com/t/JLYrOV5c

The workaround is to set the reference line from the Inside, and make the reference line offset per materials from the inside out so that you do not include minimum thickness skins.

To know this in advance would have been nice. It caused me several kinds of problems that were difficult to fix. Dimensions, precision of the model, cleanups, Intersects, Wall Labels, Schedules, etc...

[Laszlo Nagy]

I see this conversation has progressed while I was researching and typing my answer.
Anyway, Steve, what you are saying is one Viewpoint.
The other Viewpoint, the one I think the developers had is that ARCHICAD will always take whatever value you type and never overrules it. I personally like this approach better than a computer program second guessing me and rounding my input values. I want to be able to use any value I want (that makes sense of course) and not be restricted to values the program allows me.

If this rounding worked then you would be able to use only values that are always multiples of 1/64" or whatever you define in Working Units. That is restrictive in my opinion.

[Steve Jepson]

What? That is not the case for me. If I type in .01" as the thickness for a skin, it will change to read 1/64" on its own - by default. This is because if you are using feet and inches 1/64" is the smallest fraction we can display.

The problem (bug) is that this default display showing a thickness of 1/64" is not actually the thickness applied.

That is why the reference line setting that matches the cumulative thickness of the skins would not place the reference line in the correct location, whereas typing in 1/64" does.

That is not an opinion or viewpoint - that is an objective fact.

If this needs to be corrected or not is an opinion or point of view.

There is no reason to fix it if we know that is it possible that the display for skin thickness may not match the applied thickness of the skin. So if they don't want to fix it, there should be some kind of warning.

1/64" is the minimum skin thickness because any thickness less than that will generate anomalies, some of which are critical, all of which are bad.

In my opinion, leaving the 0" thickness option in this version was a mistake. It as no useful purpose and is dysfunctional. Any thing you might use a 0" thickness skin for can be done better in some other way.


See this video if you like: http://screencast.com/t/QKB7dRcv

[Steve Jepson]

for any one that may be interested, this is what happens if you try to use a 0" skin. http://screencast.com/t/JWzeMU5pma

[Laszlo Nagy]

I think we are misunderstanding each other.
You are mostly saying the same as me. And I meant the viewpoint thing on something else. Maybe, it is my English. But sorry, this conversation is taking too long for me. I don't want to explain myself again.

[Anonymous]

This is why I prefer to work on smaller items in decimal inches. As Laslo said if you are working with ffi the smallest fraction you are going to see is 1/64" regardless of what dimension you typed in.

Draw a line that is 1/128" long. That line is .0078125" long. With the working units set to 1/64", the user origin over one end and hovering over the other it reads 0". With the working units set to decimal inches set to 3 places it reads .008" Granted it's still not showing exact but you drew the line at 1/128"
and as Laslo said (I'm guessing he know what he's talking about!) Archicad does not round the number so what you type is what you get regardless of what you see in the dimension display.

.01" is 1/100". .015625" is 1/64" I hate typing fractions myself but if I don't feel like inputting 6 decimal places and I want to be accurate the I'll take the fractions all day.

Autocad 2012 has a ffi precision of 1/256" and a decimal precision of 8 decimal places. I'm guessing that the designers of Archicad didn't feel that their average customer would need to get that precise. (although sometimes I wish they had). Maybe a wish?

Hey Laslo. Is there a precision limit? If I draw a line 53.03295748671456" long will it be accurate? Just curious.

Doug

[Laszlo Nagy]

4thorns wrote:
Hey Laslo. Is there a precision limit? If I draw a line 53.03295748671456" long will it be accurate? Just curious.

Doug

I think there must be a precision limit since these numbers are stored in some kind of floating point format, but I don't know exactly what it is.
I think for practical purposes in ARCHICAD if anything is less than 0.1 mm then there is no way really for you to see it in a Dialog or Dimension value. 0.1 mm is the greatest accuracy you can set in ARCHICAD for Working Units and Dimensions.
You would probably still see that, for example, a line length is smaller than that if you zoom in very very close, but no number displayed by ARCHICAD in a Dialog or Dimension will be able to confirm it for you.

(I think at the time the guys at GS decided for it to be this 0.1 mm value they figured an Architect would never need to work with or dimension a value smaller than that; meanwhile, AutoCAD is originally a Mechanical CAD program where even smaller measurements may exist, which can account for the greater available accuracy limit.)

[Steve Jepson]

The need of working to extreme levels of precision in ArchiCAD (which I do not appreciate) has nothing to do with our need for accuracy.

It is a matter of doing what you have to do in ArchiCAD to get the necessary results - clean ups, lines showing up where you don't want to see them...things like that.

If the industry standard ffi is 1/256" then 1/64" is inadequate.

We are probably headed for NURBS modeling in ArchiCAD, 5K Super HD displays, 8K in the next year or so.

As they develop the program to be compatible with this kind of precision, ArchiCAD will have to also increase it's level of precision too. 1/64" is more than adequate for accuracy, it is not anywhere near adequate for the precision we will be needing very soon.

[Laszlo Nagy]

Steve, I just want to let you know that I will forward this to GRAPHISOFT for consideration. After all, I agree that when you type a value in a Dialog that is not the multiple of your smallest accuracy, then it would be helpful if ARCHICAD showed some kind of warning next to the field to indicate that the value you see in that field is not actually the value you entered.
It would be helpful to see that information when it is relevant.

Steve wrote:
What? That is not the case for me. If I type in .01" as the thickness for a skin, it will change to read 1/64" on its own - by default. This is because if you are using feet and inches 1/64" is the smallest fraction we can display.

The problem (bug) is that this default display showing a thickness of 1/64" is not actually the thickness applied.

That is why the reference line setting that matches the cumulative thickness of the skins would not place the reference line in the correct location, whereas typing in 1/64" does.

That is not an opinion or viewpoint - that is an objective fact.

If this needs to be corrected or not is an opinion or point of view.

There is no reason to fix it if we know that is it possible that the display for skin thickness may not match the applied thickness of the skin. So if they don't want to fix it, there should be some kind of warning.

1/64" is the minimum skin thickness because any thickness less than that will generate anomalies, some of which are critical, all of which are bad.

In my opinion, leaving the 0" thickness option in this version was a mistake. It as no useful purpose and is dysfunctional. Any thing you might use a 0" thickness skin for can be done better in some other way.


See this video if you like: http://screencast.com/t/QKB7dRcv