Revit Arch. project origin: Revit 2009 [Archive]

pfaudler

2008-11-12, 03:38 PM

We are starting a new project in Revit 2009 SP2. And i am wondering about how to go about setting up project origin? In our previous project in Revit 2008, we had moved entire project near to acad 0,0 and then link that acad survey file into revit 2008 and acquired co-ordinates from it. In this case we had to manage 2 project origins and record the difference between world OS origin and revit specific project origin.

Is it still the case with Revit 2009? The new project has X = 410199999.6000mm Y = 561500000.4000mm. Do we need to move survey acad file near to acad 0,0 and then link it to revit 2009 and acqurie co-ordinates?

I went through some posts in this forum and they were quite extensive. Lots of information on this subject. The common message was revit is not happy with your project being away more than 2km. from revit origin.

Thanks in anticipation of your help.

Regards

twiceroadsfool

2008-11-12, 03:43 PM

pfaudler

2008-11-12, 03:55 PM

Download the attachment, and import/link it in a floor plan with no crop region, Origin to Origin. (It is just a small circle drawn in AutoCAD around the origin).

That is where you want to stay centered around.

For what its worth, i did this in our template, then drew and pinned two reference planes through the center of it. One called NS ORIGIN and one called EW ORIGIN.

So whenever someone starts a new project they have a concrete starting point...

Thanks very much for your quick response.
But how is this linked with our site acad drg? Does this mean that i need to move everything in acad site drg. near to acad wcs 0,0 and then link that in to revit 2009 and acquire co-ordinates?

reagrds

twiceroadsfool

2008-11-12, 04:00 PM

I apologize. I read the post too fast, and missed that portion.

I would leave the AutoCAd file as it is, especially if its a consultants file. You dont want to be changing it everytime they send over an update.

Import it Center to Center, then move it so it is properly aligned with your model (which is built around the REVIT origin, as i described above).

THEN, acquire coordinates from the DWG file. Revit will read those *coordinates* but as far as Revit is concerned the model will still be around "revits origin" so you wont have the issues that plague models a large distance from the origin...

tomnewsom

2008-11-12, 04:16 PM

"Shared Coordinates" confuses the hell out of me so I use the Origin to Origin method as described above. Having imported Acad files that are drawn very far away from 0,0 reduces accuracy, so I re-zero survey drawings if they need it.

pfaudler

2008-11-12, 04:28 PM

Thanks very much.

I see different views here. So if we model whole revit project around revit origin (share co-ordinates not acquired at this stage), and then link final survey drg. with true world OS origin, which is shown above, and acquire shared co-ordinates from it, do you see any problems because of large nos. in x and y axes. Please see above for the x and y value.

Tom's method suggest that i would be better moving survey drg. near to WCS 0,0 in acad and then link-->>acquire etc..

thanks

twiceroadsfool

2008-11-12, 05:09 PM

No no... You dont have to move anything, in either file.

Import the file i posted origin to Origin. Build your Revit model around THAT origin as the (roughly) center point.

In the Survey LEAVE EVERYTHING where it is already, and import the SURVEY Center to Center.

It will be in the wrong place, obviously. MOVE the durvey (in revit, just grab it and move it) so its in the right spot. THEN use Shared Coordinates to ACQUIRE the Coordinate of the Survey.

Revit will still maintain ACCURACY because its still around the *Revit origin* even though youre not using the coords of the SURVEY.

You DO NOT have to go in and start moving stuff in the survey...

twiceroadsfool

2008-11-12, 05:10 PM

http://forums.augi.com/showthread.php?t=53687

That is a post in the FAQ, with one of the original developers explaining the "why's" of this method, for your educational purposes...

pfaudler

2008-11-12, 05:32 PM

Thanks a million Aaron. You have been very helful. I can now start this project with confidence. (while i await autodesk's subscription center reply on this one).

I will post some results of this new project fairly soon.

Regards

pfaudler

2008-11-13, 10:26 AM

Just got the reply from autodesk subscription center tech. support team, which says following:

My question:
================================================================
"Dear Sir:
We are starting our second projec tin Revit 2009 and site drg. in acad has origin away like X = 410199999.6000 Y = 561500000.4000. This is true UK OS origin. Now do i need to move this site drawing near to 0,0 in ACAD and then link that moved origin site drawing into revit and acquire co-ordinates from it? We did this in our previous project in revit 2008. So we had to work with 2 project origins in that case. Do we still need to do this in REvit 2009? or does revit 2009 handles large nos. in origin?

thanks in anticipation of your quick response.

Regards

=================================================================
Autodesk reply:
================================================================
"Yes, you have to do this again. Revits limitation is 3km at the moment. (This might be increase to 4, 5 or 10km in the future)"
================================================================

I am now confused. Revit tech. support team says i have to move everything in my survey drg. near to acad 0,0 and then link it. Am i right to interprete their reply?

Thanks for your help.

regards

Scott Womack

2008-11-13, 11:10 AM

pfaudler

2008-11-13, 12:01 PM

Thanks very much Scott. I hear these 2 different views on this. Earlier in this post someone said twice that we dont need to move survey drg. entities to acad wcs. and autodesk and some other friends here say we need to move.

I think it would be useful for the community, spcially to the beginners, to have a definitive answer to this. I saw many thread on this subject in this forum since 2004. the latest i could find was in 2007 Q1 somewhere??. But i just wanted to know if this is still the case with the latest 2009. Because i remember autodesk has been saying that in the future this will change. But I could see that this problem prevails since the begining, no? sorry, i dont know the history of Revit much, but reading various threads on this subject implies this.

I am relatively new to BIM world but is this the case in every BIM tools? If we have to move everything in survey drawing, which we did in previous project, then we will have 2 origins to manage through out the project. Is this how everyone else doing in Revit? Any guidance on handling 2 origins and its workflow would be very much appreciated.

So all CAD deliverables coming out of revit will have local revit specific origin and hence all M&E, structure etc. work will be based on arch. drgs exported out from revit. We will have the difference between revit local origin and true OS site origin recorded in project CAD protocol. So when project is on-site, people can work work out the co-ordinates from revit exported cad drgs.

Thanks in anticipaiton of your help.

Scott Womack

2008-11-13, 12:11 PM

I am relatively new to BIM world but is this the case in every BIM tools? If we have to move everything in survey drawing, which we did in previous project, then we will have 2 origins to manage through out the project. Is this how everyone else doing in Revit? Any guidance on handling 2 origins and its workflow would be very much appreciated.

First, this is a Revit forum, and there is no discussion of the half-dozen other BIM products out there.

Second, you need to read, and understand the Shared Coordinates commands in Revit Help File.(Not necessarily an easy topic) Shared coordinates can and will created another UCS in an autocad file. Third, the coordinates issue really only applies to site drawings. Also, you may be too concerned with coordinates when it comes to the MEP (Other than site utilities)

pfaudler

2008-11-13, 12:47 PM

Thanks Scott for your kind response. I think i know this is Revit forum but was just asking for honest and friendly view on BIM tools so that we know where Revit stands. And what could be a better way then asking it in Revit forums. But thats not a problem, i am sure i can find that info from NON-REVIT websites or forums, if i am really interested. All i wanted to know was if this is BIM (not Revit) related issue (which in our case Revit related)then we as a company who is embracing BIM technology knows what challenges are there and how to deal with it.

Thanks for your help though. I will refer to Revit Arch. 2009 help file for further reference.

Regards

twiceroadsfool

2008-11-13, 01:16 PM

Its a Revit issue, for us. This is how it was explained to me in dummy terms, but it may not be entirely accurate:

Revit has two different *engines* that are running. One for modeling, and one for displaying. They use different levels of precision, but at zero all things are equal. So as you proceed farther from the origin, the levels they are different increase, until it starts to cause problems.

That said, im CERTAINLY not saying that Autodesk is wrong... But i dont move (and refuse to move) the contents of a consultants DWG file. Maybe ive been lucky on all of our projects, and they havent been far rnough from the origin to matter, but they certainly werent anywhere NEAR the origin. It didnt matter, as i was importing them CTC anyway.

But as i said, i might have been lucky that they were all within whatever the necessary distance was.

But from a workflow/liability/repeatability standpoint, we shouldnt be going in and altering consultants files at ALL, in my humble opinion. Tonight ill have to go back and look at those consultant surveys that ive used over the last three years, and see where they relate to the WCS Origin in Acad. Im CERTAIN though, that after the discussion i had here with Dave C, that what i took from the convo was to do it this way.

Unless, as i said, there is an issue with the PREFERRED method, if something in AutoCAD is extremely out of whack.

Clear as mud? :)

chodosh

2008-12-17, 12:31 AM

...is [this a] BIM (not Revit) related issue...?

Honestly, in having banged my head against this working in four or more competing software platforms (BIM and CAD in parallel), while Revit specifically has reasonable limits, which make sense in a self-contained relational database, in my experience this has been a computational issue, neither BIM nor Revit, mostly having to do with interoperability between different software and the resolution of units in various platforms, as Aaron noted in regards to design resolution differences between modeling and displaying. All of this comes down to 1s and 0s.

Some people might sigh, emphatically, at what I am about to say because it's politicy and pie-in-the-sky idealist (deal with it ;)), but I would suggest taking a look under the hood into the IAI (http://www.iai-international.org).

What is happening with the coordinates systems is quite complex, and evolving. It has changed, and is continuing to change, but in Revit, where everything is relative, the established origin is not hard and fast, it is relative. If you're interested, I can send you a paper that will bore you to tears or to sleep or both about interoperability between coordinate systems in computer aided drafting software. But, not here.

My advice is keep an open mind, there is value in the way Revit handles internal and shared coordinates that can allow you to have multiple origins and manage multiple files within Revit and between Revit and CAD. And, that said it is not a BIM issue just because Revit is structured differently than 'traditional' CAD. There are pros and cons to both. Being aware of how Shared Coordinates functions in Revit will be a tool you can rely on if employed strategically and with planning. It is very powerful. There are also resources on several blogs, websites, and AU online classes that help explain the process that can augment the help instructions.

Good luck,
LC

Devin_82

2008-12-17, 01:51 AM

I haven't experienced a problem with the coordinates exceeding Revit capabilities yet, but in reading this I thought of a possible work around. I would like to throw it out to the group for comment:

1. After starting your project in Revit and once you have a decent footprint, export to CAD, "Revit2CAD.dwg"
2. When you first get the Consultant file, xref that file into Revit2CAD.dwg
3. Move the consultant xref to the correct location (possibly even drawing a no plot line from origin to origin that is frozen until needed)
4. Saveas "Site_Import_Revit.dwg"
5. Erase all live line work (except maybe the origin to origin line from 3.) so that the only thing left is the xref
6. Import (link) into Revit, origin to origin using the visible layers only option.
7. If you get a new file from a consultant with the same name you don't really have to do anything (maybe just some reloading), but if it has a different name you can just open the xref dialogue box, select the xref, browse for the new file and save the path, then save and close the "Import" file and reload it within Revit.

That way when you get a new consultant file you can just reload it into the "Site_Import_Revit.dwg" without having to modify the actual consultant file and reload the import file in Revit.

I did a quick little test to see if it works and it appears to be working OK for me on a simple group of files.

Let me know if you have tried this and found any problems or have anything that might improve upon this workflow.

Calvn_Swing

2008-12-17, 03:06 AM

We've used the method Aaron described extensively, with files in CAD located all over the place (easily exceeding the limits in the OP's example. Revit does not use the shared coordinates acquired from the CAD file internally, but only when exporting and importing the files. It basically applies a transform (move and rotation) to the import/export equal to the difference between the revit origin and the linked file's origin.

So, linking in a CAD file modeled out in CAD never never land has never caused inaccuracy for us. This allows you to link in civil files with no repeat modifications, no CAD workarounds, etc... I can't image why you'd do anything else.

As for why someone from Autodesk told you to move it again, I can only image that they didn't completely understand your question. That answer is completely at odds with what I've heard from other developers and the original revit crew.

My two cents: I use the support requests to ask autodesk for technical questions, report bugs, and suggest improvements. When it comes to process, I pretty much ignore autodesk completely and look for consensus on AUGI because (quite frankly) most of the people from Autodesk haven't produced a real project in Revit in some time. So, they don't really know that much about realistic or cost effective practices in Revit.

This isn't an insult to Autodesk employees, just the way things work...

Scott D Davis

2008-12-17, 04:04 AM

My two cents: I use the support requests to ask autodesk for technical questions, report bugs, and suggest improvements. When it comes to process, I pretty much ignore autodesk completely and look for consensus on AUGI because (quite frankly) most of the people from Autodesk haven't produced a real project in Revit in some time. So, they don't really know that much about realistic or cost effective practices in Revit.

This isn't an insult to Autodesk employees, just the way things work...

some of us have....I spent 8 years at WLC as a Proj Manager, and was the Revit Implementation Specialist. Before that I was at Fluor Daniel for 4 years. 12 years of experience on real projects both in AutoCAD and Revit. Almost 2 years at Autodesk already, and I've gained more experience by going to tons of firms and seeing how they do work in Revit.

eric.piotrowicz

2008-12-17, 05:09 AM

Sure we all see our frustrations as the most important items on the Revit wish list and many of us do have very good ideas but that is no reason to bash AutoDESK developers for not knowing how things get built. Think back to the early releases and their marketing, something along the lines of "how architects think" was the tag line. Yes since AutoDESK got their hands on it they are aiming for a larger group (i.e. MEP and Struct) but even though we can't call in anymore and say "we need Revit to do X' they are not blindly tossing 'code writers' in to take their best shot at getting us what we want without understand how we work.
I've recently joined a firm who is just getting on board with Revit and daily I have to weight the costs and benefits of Revit to those who last drafted on a board with a strightedge and triangle. But what is always a selling point is that the down falls are very narrow focused but the benefits can be seen thru the life of a project and beyond. SOME things will take a while to figure out/understand/incorporate and those things are a BIG problem at the time they come up but two projects down the road they are old hat and the returns far outweight the initial costs.
Deadlines suck, but two things need to happen. One is the managers setting the deadlines need to build in a reasonable amount of cushion time for us to figure out bugs and two is we need to embrace Revit for what is available and not expect to get the perfect solution the first time. How long did it take before all of us once AutoCAD junkies started using blocks to their full potential? Sticky backs were the most efficient thing before that and prior to sticky backs we had literally cutting and pasting with scissors and tape. The point is all these things took time to be adopted by the industry and the transition to Revit is no different.
There will always be growing pains, choose to grow with them.
Cheers to the Reviteers :beer::beer::beer:

pfaudler

2008-12-17, 12:27 PM

A very interesting dicussion here. Thanks all of you for sharing your knowledge with us beginners in Revit. To be honest, today's discussion between you experts out there falls beyond my current Revit knowledge.

But back to my original question. I just want to let people know that after getting mixed responses on moving origin to 0,0 in acad and hence in revit, to be on the safe side i decided to move everything to 0,0 in acad and acquire shared co-ordinates in Revit on this project. I dont agree on working in this way but at the end being a CAD(BIM?) Manager if i have to manage the project workflow then i have to go with the safe option.

I also got following response from Autodesk on this subject.

=================================================================
Dear Rahul shah,

Yes, move it to 0,0,0. Normaly you should also draw in AutoCAD close to the origin.

Best Regards,

August Weinzierl
Autodesk Support Team

=================================================================

We have third Revit project starting in January and the site falls within 2Km Radius from acad 0,0. I believe i dont need to move origin for this project as it falls within 2Km and Revit 2009 can handle upto 3Km limit. am i right?

Regards

twiceroadsfool

2008-12-17, 01:48 PM

Im certainly not one to refute what Autodesk says is best practice... Obviously they know the caveats of their software much better than i do.

But- however young and short on experience i may be- i can state the following with confidence: Im not sure how you mitigate risk or maintain any sort of QC system when you have to go IN to your consultants files to make major changes like relocating every object in the drawing. Its just not a workflow i would EVER support using.

1. Everytime you get a new file from them, you have to REDO those changes.

2. "You dont know what you dont know." I liken this too: maybe some of what is on their *drawing* is part of an AutoCAD model, that has the AutoCAD version of constraints on it, or something. (I dont model in autocad, do they even have constraints? lol). if they do, im just picking everything up and moving it on a whim that things hold together? What about what objects i CANT see?

I completely understand what support is saying, and if i *personally* am drawing in AutoCAD OR Revit, ill start at the origin and maintain some proximity to it. But we all know it doesnt fly that way when were GETTING files from other people. Other consultants on the team arent always likened to "moving" their entire drawing off whatever coordinate system they used.

Anyway, im glad your project worked out, but thought id provide the explanation for why i stated that theres no reason to move ANYTHING in the other AutoCAD file. As Kelly stated, weve gone through projects that have autoCAD stuff out in Hyperspace, and using the CTC, move (in Revit) and acquire, weve had ne'er an issue.

If support is SUGGESTING moving the items in AutoCAD would be BETTER and MORE CONVENIENT, i udnerstand... But understand its NOT a necessity.

sbrown

2008-12-17, 04:02 PM

I will say this. In my experience the only "safe" way to proceed on very large sites 1000acres etc. is to move the cad data close to 0,0,0. I record the exact distance x,y so it can be repeated easily. the reason I say this is on large site cad files from civil engineers I've had them magically move when reloaded when I've used Aaron method.

Aaron's described method is the "correct" workflow. I have personally had it fail after many months on a project of working fine, all of a sudden some of the linked dwgs move miles away. I can't reproduce it, The cad file hadn't been worked on since we received it. I think on small jobs where the site is far from 0,0 you will be fine. But my experience with acquiring coordinates has been troubled.

Note these are projects with over 12 sep. building models linked into a 700 acre portion of an island where the cad data's 0,0,0 is very far away 119miles to be exact.

I wish I could trust the method Aaron described. As it is now. I place Property lines in ALL revit files so when the coordinates "explode" on my I can re assemble.

I have heard , yet to try, that if I were to add a line in the cad file from 0,0,0 to the property line, then I would not get the magical moving dwg files. I hope this is true.

Has anyone else experienced this?

twiceroadsfool

2008-12-17, 04:19 PM

Interesting... I havent experienced that as of yet, but i havent worked on a site THAT large yet, either. Maybe id be singing a different tune if that had happened.

This is one of those issues that needs to be rigorously tested , so that someone at the Back of House can determine exactly WHAT is going on. Whats causing the coordinate hop, whats causing the Shared Coords to fail, and moreso.... At what QUANTIFIABLE distance.

If what youre suggesting is really happening (and i have no doubt that its exactly as you described), then we (both end users and the factory) need to know what is doing it, so we know what were avoiding, lol...

sbrown

2008-12-17, 04:57 PM

Yes, this is a tough issue for those involved in multibuilding projects. The other thing I don't like is NO way to undo shared coordinates if a user messes up. For example, we had a tiny villa building linked into the site model, then the buildings posistion was published, then the site linked back into that model. then someone accidentaly or purposely moved the site in the villa model and saved, this moves the site in all other models. So there is no heirarchy since it bi-directional. Basically what I'm saying is I'd like to control all coordinates from the site model which is set to true north where all other buildings are project. So someone doesn't accidentally do something affecting multiple linked models. Its probably a rare occurrance but very painful to track down which model caused the problem.

mariusaln

2009-01-26, 09:10 AM

Hi!

I`m struggelig with this Revit issue aswell. When I import any cad survey to my projects with origin to origin, I get a message that objects are at a large distance and center to center option will be used. I have linked in multiple cad-files in my project and all the site cad files are at their original coordinates. These coordinates are around x: 14000 and y: 495000. The thing I don't understand. Won't yor cad-site get some new coordinates if you move it close to 0,0,0? How can u use Acquire Coordinates and get the right coordinates when your cad-file is on a totally different place than the original?

I have tried to import dwg-surveys into the revit project using the center-to-center option and then use Shared Coordinates--->Specify coordinates at a point. It seems to work in the start, but after a while my different dwg-files are moving to totally different places in my revit project. This happends when I reload my linked dwg-files.

Could someone please help me out with this problem, and maybe send me a basic "step by step" guide to get this right?

Regards

diesellam

2009-01-26, 09:28 PM

I'm still pretty much a newbie in Revit so the following is just my 2 cents.

I thought in AutoCAD, your reference point is always (0,0,0) meaning
the point can either be at one corner of the builidng or an intersection point of 2 grid lines. And this is the exact same point they are going lay on the job site before the construction proceeds.

But based on what I've read so far, it sounds like you want the "center" of the entire project to be (0,0,0). Wouldn't it create more problem (like tying this point back to the grid lines to locate it)?

I agree that we should NEVER move the consultants drawings to match our revit file because it defeats the whole purpose of having the same reference point for everybody. Plus we become liable to modify their drawings which they can claim they never do.

I would love to hear what other expects in this forum can suggest in this issue.

mariusaln

2009-01-28, 12:32 PM

Hey again guys!

I`m still struggeling with this problem. My dwg-files are moving around in my revit project from time to time, and it happends often when I reload a dwg file. I have followed the instruction you have mentioned, except from the part that you should move your cad-file to the 0,0,0 point in autocad. If you do that, you'll get some totally different coordinates in your consultant drawing. And you will not get the correct coordinates from your autocad linked file when you Acquire coordinates.

Am I missing something here?

Edit: Seems like the dwg-files moves to the coordinates they originally had before I Acquired coordinates. Around the 0,0 revit coordinates. i still can't see what I`m missing here...

cphubb

2009-03-23, 04:35 PM

This is a little off topic, but we were just experimenting with the size limits in Revit 2009 and discovered something different.

1. We found the limit is 30,000' not 3km.
2. That limit is only input based, (we cannot type a valuer larger than 30,000')
3. We were able using copy and just drawing to create a box 250,000' on each side.
4. No reason we could not go larger but why

We also drew a box similar sized in ACAD and it imported CTC just fine. Exploded file and is editable as long as the editing values are 30k or less

pfaudler

2009-06-01, 03:12 PM

Has anyone got the latest info on this for Revit 2010? AutoDesk, what do you say?
Has Revit 2010 sorted this out? Or Do we still need to move project origin near to Revit 0,0 and record the difference?

Thanks in anticipation of your help.

Regards

twiceroadsfool

2009-06-01, 03:27 PM

A couple of things on this subject:

1. In response to cphubbs comments: The limitation is not simply "input based." Its computation vs. display based. Drawing a box that is 250,000' wide in Revit is great... Now put a wall on that line, and try to detail a section. Youll be playing whack-a-mole, except instead of the ribbon, youll be trying to click on the wall with detail components, and it will shift awkwardly every time you zoom in or out. Itll also start to crash in the view. The limitation is MUCH more than input based, and it starts to rear its ugly head at or around 1 mile from that Revit Origin.

2. I havent tried an extremely large site since getting in to Revit 2010, so im ASSuming this limitation is still present. However, since autodesk spent considerable time playing with the new graphics engine, id be curious to hear their take on it. I think its probably still an issue.

We, as an office, are keeping our workflow the same as its been. We're not editing consultants files, period. We have that benefit, since we havent run in to the site suddenly shifting, as Aaron (the other one) encountered. If and when that occurs, i will start to look in to XREFing the consultants files in to a blank CAD file, and adjusting THAT. I simply (and blindly) refuse to edit a consultants work.

cphubb

2009-06-01, 04:03 PM

Aaron,

We have not seen any of the crashing or jumping you note at the long distances from the origin. We have noticed some wierd rounding problems with dimensions, especically the temporaty dimensions. I still do not recommond drawing that far out unless there is a good reason, but using Shared Coordinates and Linking should solve that.

We also have not seen any movement on the CAD files we link in. We either use Origin - Origin or CTC. We move the file as needed and if the CAD side stays stable ours does as well. WE have only had problems when the other CAD users do not us good practices like moving the drawing up and over 100' to try a new layout instead of drawing at the origin. Most of our CAD comes from the Survey and Civil guys who excel an managing the origins and rotations so we have very few problems. Our structural engineers seem to be the works about managing their origin and moving or rotating stuff without informing the rest of the team.

twiceroadsfool

2009-06-01, 04:26 PM

Shared coordinates will NOT resolve the issue of the items getting difficult to work with a large distance from the origin. It MAY be that in a brand new file, putting a wall 250k feet away will work and look alright in section, but i promise you: Start to really detail a project out there, and youll end up in the hurt locker.

Shared coords does not actually *move* the native origin, and itll still be an issue. This has been highly documented before...