Origin Ideas

[ron.sanpedro]

The company line on origin in Revit is that you just don't need to worry about it until you do Shared Coordinates, but it seems to me that even very early on, knowing where the origin is, and it being rational, makes some sense. To that end I am looking at doing two things in our office templates.
1: Create a copy of Level 1 called Origin Coordination and insert and pin a DWG origin to origin. The DWG will be nothing but some Layer 0 cross hairs. Then...
2: Place Grids A and 1 such that the intersection is at the origin, and move the Elevation Tags as needed.

Now I have established where A and 1 go, and established a rational origin that complies with office standard ideas about grid sequences, and long before I have a Shared Coordinate established, I will have something rational for consultants to work with.

I am wondering if anyone else has tried this, with what results? Have you had issues where people have deleted the ORIGIN view? Moved the DWG so it was no longer a valid reference? Deleted the grids and put them somewhere else on a whim? All are training and standards issues in my book, but I am wanting to be prepared, since I will be asking people to think more as they start working on projects, and that never goes over well ;)

Thanks,
Gordon

[jcdecastro]

Gordon,

The origin will matter just about as many times people actually draw plans and details even remotely close to the origin....next to none. :lol:

I would suggest that you link a dwg with a line at the origin going off at an angle, then draw the ortho lines with either revit invisible lines or reference plans ( and maybe label them X and Y) The reason to draw the lines in revit instead of in the dwg is to try to get away from the "line is slightly off axis" revit import bug :p ...ok I might know be a bug but it sure is annoying like one. Then pin them.

And that is yet another reason why 0,0 doesnt matter...the average user can move those ref planes see a little pop up in the corner and click ok. LOL. Origin gone.

I am learning not to fight with revit while going through the office implementation phase, not to cut against the grain. If the developers wanted us to know where 0,0 was they would put it there, like those ugly elevation tags.

[Mr Spot]

You can use spot co-ordinates to locate the origin in revit without any need to use a dwg import...

The reason why it doesn't matter where the origin is in revit is because at any point where you find the origin does matter, simply goto settings-->shared co-ordinates-->specify co-ordinates at a point, pick your point and co-ordinates.

[edit: Provided you begin your model around the Revit Internal 0,0,0]

Your done....

[Wesley]

Chris has it.... so easy to respecify an origin, no need to prespecify at all. Also, I would be VERY leary of putting in a DWG you don't need. Those damn things really clutter up your files. We work hard to have no DWG information in our files whatsoever - not even in any of our families. You can't generally get away from a survey in DWG, but that ideally would be the only one... even that one we're trying to get rid of. We are getting some of our surveys supplied in Revit now...

Cheers,
Wes

[adb]

You can use spot co-ordinates to locate the origin in revit without any need to use a dwg import...

The reason why it doesn't matter where the origin is in revit is because at any point where you find the origin does matter, simply goto settings-->shared co-ordinates-->specify co-ordinates at a point, pick your point and co-ordinates.

Your done....

Hummmm....I want to make sure I am understanding this because if you do specify co-ordinates at a point in Revit and move 0,0,0 wherever you want, then revit will actually list that new point to be 0,0,0.

HOWEVER, that has not really moved that point as far as the project internal co-ordinate system is concerned. The reason I say this is once you have moved the co-ordinate, then when you export out as an Acad file then you must go to options and change the co-ordinate system to "shared" instead of "project internal". If you don't choose "shared" but instead leave it as the default of "project internal" then your exported Acad drawing will report the old 0,0,0 location.

Am I missing something? I know there has been threads on this subject and when I read them, I thought I understood what was going on.....that is until I read this thread.

We share files all the time with consultants who are still in Acad so I am very concerned with co-ordination of the origin as it goes from Revit to Acad and back again.

Thanks.

[twiceroadsfool]

The reason why it doesn't matter where the origin is in revit is because at any point where you find the origin does matter, simply goto settings-->shared co-ordinates-->specify co-ordinates at a point, pick your point and co-ordinates.

Your done....

Actually, this is very much not the case. Revit DOES care where the origin is, relative to your modeled geometry. The reason i got from tech support is that there are two "engines" running in Revit: One for the modeling, and one for the graphics display, and they have varying levels of decimal precision. So the farther you get from the origin, the more problems you start to have. And believe me, weve had our share.

We have a model that was built based on site drawings being linked in OTO, and consequently our Building is roughly 19 miles from the Origin. Windows fail to open, detailing wall sections is difficult because you have to select "ghosts" of objects, because the cursor doesnt land on the objects themselves.

To clarify, using the "Specify Coordinates at a point" will change which point Revit *says* is the Origin, but it will not cure your problems that arise from being too far from the *native* Origin.


Gordon-

Getting back to your original question: In our new RAC2008 template, we did something very similar. In setting up the template, i imported an origin circle. (Consequently, in the template that ships from the Factory, it is EXACTLY in the middle of the 4 elevation markers...). I then went and set two reference planes (N/S and E/W) and named them and pinned them. I didnt go with grids because every project has different needs, and some may be angled, etc. If people delete the grids, were back where we started, lol. I *think* i left the DWG in the linked files, as well.

[Wesley]

Actually, this is very much not the case. Revit DOES care where the origin is, relative to your modeled geometry. The reason i got from tech support is that there are two "engines" running in Revit: One for the modeling, and one for the graphics display, and they have varying levels of decimal precision. So the farther you get from the origin, the more problems you start to have. And believe me, weve had our share.

We have a model that was built based on site drawings being linked in OTO, and consequently our Building is roughly 19 miles from the Origin. Windows fail to open, detailing wall sections is difficult because you have to select "ghosts" of objects, because the cursor doesnt land on the objects themselves.

Yes, I'll pay this. There is definitely a problem with long distances to an origin. A problem to which I was not speaking directly (though perhaps I should have...). In Australian terms, many large projects are required to work to 'Australian Map Grid' (AMG) which often creates a situation in which the origin point is a very long way from the project. If you do not setup the original co-ordinate relationships correctly, you can get ALL SORTS of problems (all related back to floating point precision in the Revit engine).

I didn't think the question was specific to origins at great distances however, but simply how best to account for ANY origin point in the initial project setup. Indeed, if we are referring to a template, you cannot yet know where the DWG origin will be at all! Gordon's pinned DWG is an abstract for setup, not a real project.

Also, you can place grids and pin them to the intersection at the origin point using Revit objects without bothering to put in a DWG (I've stated my objection to unnecessary DWGs already)


Getting back to your original question: In our new RAC2008 template, we did something very similar. In setting up the template, i imported an origin circle. (Consequently, in the template that ships from the Factory, it is EXACTLY in the middle of the 4 elevation markers...). I then went and set two reference planes (N/S and E/W) and named them and pinned them. I didnt go with grids because every project has different needs, and some may be angled, etc. If people delete the grids, were back where we started, lol. I *think* i left the DWG in the linked files, as well.

I moved the origin point in the Revit template to the centrepoint of the elevation markers back in Revit 7.0, when we first started doing this work for Autodesk. At the time it was simply a convenience and logic question (it has to be SOMEWHERE, right?). Oddly, before that, it was just to the right and below the east elevation marker.... which kind of indicated RTC's own attitude to the importance of the origin location...

I think the idea of using named reference planes rather than grids is a good one. You might consider non-compass naming as well (left / right, top / bottom) so it doesn't conflict with renamed elevations on rotated projects.

Cheers,
Wes

[tomnewsom]

That AMG sounds very silly - plenty of CAD systems have accuracy errors far from the origin.

We do the process as outlined in the OP - we import origin-to-origin a DWG with crosshairs at 0,0 and work from there. It make dealing with consultants who use autoCAD so much easier - no fussing with shared coordinate systems and extra UCS references etc. The origin is the origin and you can't get it wrong. Works well for us.

[jeffh]

In the out of the box templates the origin point for Revit is right in the center of the elevation markers that are in the default templates. If you start drawing you building in the middle of these elevation markers your geometry will be close to the origin. The corner of the building or a grid line might not be exactly on the 0,0,0 point but it will be close enough to not really matter.

Maybe I am missing something?

[Calvn_Swing]

Jeff,

I think you're dealing with the anal-retentive factor here, plus years of ingrained practice worrying about the origin in CAD.

To me, knowing that a spot on my building is at the origin is important for a variety of reasons. 1) For import and export to other programs. Knowing where the origin is means I can predict where my file will come in, and where other files will come in. 2) It just makes me feel all warm and tingly inside to know I'm right on the 0,0,0.

Just like it makes me warm and tingly to know my dimensions are spaced an exact distance away from the building, or that my grid heads are always 10' from the edge of the building, or that my text notes are exactly spaced on the sheet, etc... Lining things up consistently makes me feel content inside. Any, Revit just doesn't let me do any of these things. I've gotten used to it, but whenever I'm placing my building in a new template file, or running a dimension string, or anything else like that, I still long for the snaps to measure off of modeled geometry as well as other dimensions...

Sigh...

[twiceroadsfool]

Yes, I'll pay this. There is definitely a problem with long distances to an origin. A problem to which I was not speaking directly (though perhaps I should have...). In Australian terms, many large projects are required to work to 'Australian Map Grid' (AMG) which often creates a situation in which the origin point is a very long way from the project. If you do not setup the original co-ordinate relationships correctly, you can get ALL SORTS of problems (all related back to floating point precision in the Revit engine).

I

It seems to me that this AMG requirement would be he perfect reason to use the Shared Coordinates, while still centering your model around the "Revit Origin" that i decsrived above.

Construct your model around the "native revit origin," and import a DWG of a site drawing that is using AMG coords, but impot it Center to Center. Then align it with your building so the site is in the correct corresponding location, and then use Acquire Coordinates from the AMG site file to relocate the "origin" to the AMG. Youre model wont get ansy from being ten miles away, and when you import/export you will still be on par with the AMG site.

The only gripe with this is the inability to use crop regions, etc. Unless that changed in 2008.... I havent tried it yet.

[jeffh]

Jeff,

I think you're dealing with the anal-retentive factor here, plus years of ingrained practice worrying about the origin in CAD.......

Yeah I can understand the sentiments you posted. I started my drafting using AutoCAD too and remember all of those things. I guess we have just let them go. In reality I don't think any drawings I have done since have suffered because of it. :)

That being said I do understand the need to know the origin when exporting/importing with other programs. This is why shared coordinates exists.

[tomnewsom]

Yeah I can understand the sentiments you posted. I started my drafting using AutoCAD too and remember all of those things. I guess we have just let them go. In reality I don't think any drawings I have done since have suffered because of it. :)

That being said I do understand the need to know the origin when exporting/importing with other programs. This is why shared coordinates exists.
Except that shared coordinates add a layer of complexity in the process that doesn't need to be there if you know exactly where 0,0 is!

[ron.sanpedro]

You can use spot co-ordinates to locate the origin in revit without any need to use a dwg import...

The reason why it doesn't matter where the origin is in revit is because at any point where you find the origin does matter, simply goto settings-->shared co-ordinates-->specify co-ordinates at a point, pick your point and co-ordinates.

Your done....

But the problem is those Shared Coordinates are real global coordinates are going to be very important later, when you are working with your Civil Engineer, and you will need to set them to something rational relative to the site, but early on you just need to be able to work with your DWG based Kitchen consultant, and be able to tell them 0,0 is somewhere concrete, not some loopy "over there in the lobby, near the big ficus". The intersection of Grids A & 1 is a location that exists in every single project, and it makes sense as an origin, especially for the Project Origin. I agree it means nothing when you are working solely in Revit, but we are probably nearly a decade away from that, and even then I don't know if the little mom and pop kitchen consultants and such will be Revit based. So as long as we are working with DWG based consultants, and asking them to be team players, we kind of need to be the same in return, and manked up origins, even just something floating about randomly, is a PITA in Acad, and thus something I think we as Revit users need to address. It is hard to complain to the consultants when the first thing we do is mess up their day, and then gloat about how good it is over here in Revitland ;)

Now it occurs to me to ask another question here. Are you all dealing with a Shared Origin that does in fact locate relative to the building grid, even with Civil, or do you import the shared coordinates origin FROM the Civil, and thus have an origin that makes no sense at all to anyone but the Civil engineer, but that you can safely ignore in Revit? Perhaps the answer is to set the Shared at A1, then push that out to everyone, including the Civil? It seems that the Shared Coordinate import is really where the problems are.

Thanks,
Gordon

[twiceroadsfool]

Except that shared coordinates add a layer of complexity in the process that doesn't need to be there if you know exactly where 0,0 is!

If you know right where 0,0 is, there isnt really an issue. You go through the one time feat of pulling in your site CTC and moving it, then acquiring the coordinates, and youre done.

Where i think the Shared Coordinate system is muderous, is that once youve done the above, simple items that used to be useable (like crop regions, for example) suddenly cannot be used or the Shared Coordinates do not work on export and import.

THAT, is the deal breaker. Once that is solved, Shared Coordinates will be just about perfect. IMHO, its BETTER than aligning everything to a "common" Origin. Id rather not have to dimension off some arbitrary point 10 miles off, just because im working on a large mall, thankyouverymuch. :)

[sbrown]

Be very careful with what you are suggesting. YOu don't want to use the shared coordinate tool to specify your "project" origin. then you will limit your ability to export to a surveyor or civil plan. There is NO way to move revits internal coordinate system which is what counts.

So I think the idea of knowing where 0,0,0 is in Revit is important. Especially in multi building scenarios.

Do not think that specify coordinates at point will fix anything. It will only change your shared coordinates to that point. And exporting shared has many issues with it, especially if dwgs are linked in.

[twiceroadsfool]

Be very careful with what you are suggesting. YOu don't want to use the shared coordinate tool to specify your "project" origin. then you will limit your ability to export to a surveyor or civil plan. There is NO way to move revits internal coordinate system which is what counts.

So I think the idea of knowing where 0,0,0 is in Revit is important. Especially in multi building scenarios.

Do not think that specify coordinates at point will fix anything. It will only change your shared coordinates to that point. And exporting shared has many issues with it, especially if dwgs are linked in.

While im probably articulating it very poorly, what you said is what i was trying to say, lol. You have to know where it is regardless, but that you shouldnt use it in the fashion of "since its here in our drawings of the building next door, ill just move 1000' east of the Intenal Origin and start modeling..."

The origin is a tough topic for me to find the correct terminology to describe, LOL.

[Mr Spot]

Wow, didn't realise I'd hit so many nerves on that one... :)

The reason I wrote what I did is:

A. I know our internal origin is with our elevation markers on our template file and all new projects are centred on this point.

B. As far as I consultants are concerned as long as the co-ordinates system is consistent and doesn't change mid project they don't care about its exact locations. Just as long as they don't have to start moving about their xref's every time they link a new model of ours... (expecting arguments over this one... But we have never had complaints from our consultants and I've mentioned it to them)

C. When co-ordinates start to matter for us is in campus projects and typically these are based on AMG from the Surveyor. In which case I then acquire or position the correct co-ordinates.

D. When working with links with shared co-ordinates you can have multiple co-ordinate systems for your links depending on what files they are linking into...

I was just going on what works for us and the fact that we've never had any complaints because we are consistent. When things start moving about is when the consultants have a nana.

My 2 cents.