Tollerance/Forgiveness for Dimentions

[ben]

I'm wondering if there's a way to allow for a tolerance or forgiveness for dimensions? I don't mean as in rounding to the nearest 1/8th or 16th of an inch. I mean I'm trying to get a dimension if two things are running parallel, but not perfectly parallel and the dimensions will tell me it cant do it because they are not exact. I pull an angle measurement and they are at a whopping 90.000001ᴼ. I have never seen a tape measure that goes beyond 16th" let alone 256th". when measuring the difference between the CL's it is literally 1/256" off in the distance of a 20' run. Is there any way to have an allowance or forgiveness or any kind of permanent dimension that will allow you to be off by that miniscule amount so it can still give you a measurement?

I know accuracy is important, but before I get told that accuracy should be within 256th of an inch. Let's put things in perspective. 256th of an inch in the span of 20'. There are 5280' in a mile. 5280' divided by 20' = 264. 264 - 256 = 8. That means if this run would continue to be off by 1/256" per 20' for 1 mile that after a mile it would be off by 1 8/256". Not bad in the real world if you ask me.

[ToanDN]

No.  Revit is too smart at picking on model inaccuracies that makes it dumb if you look at it from the contractor POV. 

Anyways, accuracy in the model is important, not because it makes any differences in the field, but to ensure the model integrity, and avoid errors, often times fatal ones,  down the line.  For example, a column and a slab can join well if the edges overlap more than a certain distance  or meet exactly.  But if the edges overlap too small of a distance, it can throw error and refuses to join.

A small inaccuracy can magnify to bigger ones easily.  Let's say you have a wall @ 0.001 degree from another, use mirror it several times using the other one as the mirror base line thinking they are parallel and you can end up with a mess.

[ben]

Any suggestion for a work-around just for the sake of getting a dimension pulled?

[barthbradley]

Don't you have temporary dimensions displaying for the element when you select it? 

Also, out of curiosity: do you have many warnings in your project? 

[ben]

Yeah, but temporary dimensions aren't giving me the dimensions that I need. It gives me the length and the elevation at both ends (theres no slope so its the same at both ends). It doesn't give me the center-2-center measurement between two elements running parallel.

[ToanDN]

Use TAB to pick the end point as a witness instead of the line.

[barthbradley · Accepted solution]

Sounds like you're walls aren't plumb. You don't want to fix it? Then don't dimension to it. Dimension to a Ref. Plane...a straight one. 

[ben]

It's actually piping in a hallway. Someone somewhere though a 55 degree angle hallway would be a good idea. The engineer had the original piping so screwed up and had it drawn running completely out of square with the hallway. I drew in detail lines where my piping could go exactly at 55 degrees for all of my piping and tried to align my piping to the detail lines. Unfortunately, some of my pipes are at 54.99 or 55.01 degrees instead of 55. It's literally only off 1/256" in a 20' length, not enough to actually effect anything in the real world, but enough to not be able to let me place a dimension.

[ToanDN · Accepted solution]

Have you tried using TAB when you pick the dimension witness to?  It should work.  In the future if you need to layout a bunch of pipes or ducts or whatnots at some odd angle, turn on the Workplane and rotate it to that angle.  That can ensure you draw stuff follow the angle precisely without add a bunch of reference planes, drafting lines, etc...

[ben]

Unfortunately using tab doesn't work either, but I love the idea of rotating the reference plane!

[barthbradley]

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@Anonymous wrote:

I love the idea of rotating the reference plane!

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I thought you might. That's why I suggested it. 

[ToanDN]

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@Anonymous wrote:

Unfortunately using tab doesn't work either, but I love the idea of rotating the reference plane!

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That's strange.  TABBING has never failed me.

 https://knowledge.autodesk.com/community/screencast/7e05cbec-591c-44c4-ae70-ae699b7af61c

[Sahay_R]

Would rotating the Workplace mess up anything else? Future dimensioning, text, etc? Of course, I can re-rotate the Workplane back to its original position. Then would that mess up the original skewed dimensions? (I don't think I am making very good sense here.....)

[ToanDN]

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@rsahayUZMK9 wrote:

Would rotating the Workplace mess up anything else? Future dimensioning, text, etc? Of course, I can re-rotate the Workplane back to its original position. Then would that mess up the original skewed dimensions? (I don't think I am making very good sense here.....)

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No.  You can rotate it back to right angle whenever you want.  Pretty much like  SNAPANG variable in AutoCAD.  If you working on project with multiple orientation you will love it.

[Sahay_R]

@ToanDN Thank you! Learned something new today!

[ben]

@ToanDN Here's the real kicker. I can pull the dimension on my regular floor plan view, but, as you know, you cant put 8,000 dimensions on an overall floor plan and still expect someone to be able to read it. I am trying to put the dimensions for each individual spool piece onto spool sheets (which are just views and schedules on a sheet) so the prefab shop can see all of the dimensions on how and where to place the piping on the racks for each individual spool piece. Then I will just put hanger location dimensions on the overall plan so it's cleaner and easier to read for the guys in the field. I can put the dimensions on the overall print and most of the spool sheet views, but for some reason a few of them will not let me place dimensions.

Screencast will be displayed here after you click Post.

e22116b5-fa2a-4536-a26f-ed0dbd7d31a7

[gjcLSUTP]

There should be an option to not be allowed to divert from a 1/16 dimension grid. 

the old fellas at the office told me AutoCAD was able to do that - For all the constraints it takes to make any family or any decent model, I don’t get why they can’t just make even an 1/8 of an inch as the bare minimum

I could go on, but the fact is a 1/256th for anything but exceptional projects (idk a nuclear reactor??) is ridiculous and it’s amazing to me if anyone can defend that