topic Re: Survey Point - Rotation from True North - IFC & DWG in Collaboration with other software

Survey Point - Rotation from True North - IFC & DWG

Aaron Bourgoin — Thu, 07 Aug 2025 08:10:34 GMT

We are working on a large project with 4 other architecture firms - all using different modeling platforms.

I issue an IFC containing the Site boundaries as both an IFC and a DWG. Both thtanslators reference and privilege the Survey Point.

In Autocad, the file opens with Autocad's origin at the survey point and rotated to True North. Ditto the IFC file.

Is there a way to export files as illustrated - not using True North, but rather the Project North?

Re: Survey Point - Rotation from True North - IFC & DWG

Marc H — Thu, 06 Apr 2023 00:29:22 GMT

Hi Aaron,

Is there a particular requirement for having the site file open with project north?

Re: Survey Point - Rotation from True North - IFC & DWG

Aaron Bourgoin — Thu, 06 Apr 2023 14:41:56 GMT

It would be my preference (as the central model manager) as we are overlaying 6 buildings from 4 different offices, working in three different software platforms.

Re: Survey Point - Rotation from True North - IFC & DWG

Marc H — Thu, 06 Apr 2023 23:31:56 GMT

Hi Aaron,

Sounds good. I’ve managed a few multi-building campus surveys and concurrent teams’ building projects over the years and they are a great opportunity. Might I suggest the following approach:

1. Keep the site plan true north with your ‘campus’ plots amply in the +/+ quadrant (as you have in your exhibit). (Civil likes it that way and you can overlay other surveys and aerials with ease.)

2. For each building, whether existing or new, establish what I call a ‘building origin point’ (BOP) and a directional rotation value on that point to site each structure. (The easiest BOPs are easily surveyed SW corner or grid intersection.)

3. Provide each architect with these values for use on their project/s. (This can be via a 2d or 3d file they can reference in.)

4. They model their building orthogonally and can exchange their files orthogonally with you and/or with others as needed, using agreed upon outfile formats (e.g., PLN, RVT, IFC, SKP).
5. When site visualization or coordination is needed, the buildings are inserted (or externally referenced) into the site using their respective BOPs. Once anchored, simply rotate each building file on the given BOP value to match to true direction. This should give you accuracy across the campus within a few inches, variances normally occurring with existing buildings not built straight or built off from recorded data.

6. Site MEP can follow the same logic, belonging to the appropriate building project BOP or an assigned block of the site.
If you have any detail questions or need a sample, please message me.