topic Re: Toposurface elevation measurement differs from levels in Revit Architecture Forum

Toposurface elevation measurement differs from levels

chhuanmawia18 — Tue, 02 Jun 2020 17:40:46 GMT

in this project i have kept both project base point and survey point at ground level , but when creating toposurface when i enter 0 as level , it cretes it at the bottom of the objects . Why is this?

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 17:49:13 GMT

Where's your Internal Origin at? That the Zero Origin for Toposurface Internal Points.

Project Internal Original = Project Base Point Startup Location

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Thu, 04 Jun 2020 18:01:23 GMT

it is because you moved PBP in clipped state.

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Tue, 02 Jun 2020 18:22:30 GMT

https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/screencast/Main/Details/1fdb453c-18e1-4a67-b985-f134a7675746.html?_ga=2.48144615.1366906480.1591042438-1695687343.1589915502

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 17:59:21 GMT

FWIW: The Toposurface POINTS (the points you place while inside Toposurface editing mode) are relative to the Internal Origin of the Project -- not the Project Base Point. So if you set the Absloute Elevation to zero and place a Point, it will be placed at the IO's Plane.

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 18:05:18 GMT

...I'll add that if you move the Project Based Point while CLIPPED (2019 and earlier), everything moves. Essentially, it's smoke and mirrors though. Really, only the Survey Point is moving.

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Tue, 02 Jun 2020 18:21:29 GMT

Something is wrong with the site, I cant insert the screencast in the post, so I'm just gonna put the link below. This screencast shows the problem and the solution...

https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/screencast/Main/Details/1fdb453c-18e1-4a67-b985-f134a7675746.html

Yes, the topography points are relative to the internal origin. But, moving the PBP in clipped state is like sending people into a warm hole. After they do that, they don't have any idea where that internal origin is. After all this time, I am still confused with Revit coordinate system. All I know is that autodesk help says "unclip before moving PBP or SP". So, here this screencast shows what folks can do if they forgot to unclip and suddenly got themselves swimming in a warm hole.

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 18:21:46 GMT

Locating the Internal Origin in pre-2020 versions is done by right-clicking on the UNCLIPPED Project Base Point and clicking "Move to Startup Location".

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Tue, 02 Jun 2020 18:24:49 GMT

In this screencast I did just that, but that wasn't enough to fix the issue that this member is having.

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 18:31:06 GMT

Where are you receiving your insight from? Have you worked with this OP regarding this issue before? I only see the OP's one post and no follow-up posts from him/her.

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Tue, 02 Jun 2020 18:44:43 GMT

I'm not sure if I understood the question well. Do you ask me what is my source? I had to work on some projects that I got from a 3rd party. Those projects had this issue. I busted my head about this and then just experimented...

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 18:48:33 GMT

No, you misunderstood me. You said above "that wasn't enough to fix the issue that this member is having". How do you know this?

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Tue, 02 Jun 2020 19:21:21 GMT

I'm using English for more than ten years and sometimes still say things in a wrong way. So, I apologize for that. What I meant was:

"A long time ago, I had a similar issue like this member has now and just moving PBP to start up location wasn't enough to fix it"

The topography point elevation is the absolute one and if its value is zero and at the same time ON the ground level, we can only assume that what this guy wants is to match the ground level elevation with the sea level. Well, now he can't do that cause he moved PBP when it was clipped.

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 19:45:29 GMT

@Ilic.Andrej wrote:

we can only assume that what this guy wants is to match the ground level elevation with the sea level.

Well, that's the case, then all the OP needs to do is drag the Toposurface up in Elevation/Section View.

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Tue, 02 Jun 2020 20:05:01 GMT

@barthbradley wrote:

@Ilic.Andrej wrote:

we can only assume that what this guy wants is to match the ground level elevation with the sea level.

Well, that's the case, then all the OP needs to do is drag the Toposurface up in Elevation/Section View.

Yes, but then if he adds new toposurface points afterwards, everything will be messed up again. He would need to move the toposurface down then back up and so on, undermining the fact that the coordinates are messed up.

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 20:29:48 GMT

Coordinates? I am not following you. Spot Elevations and Contours labels, and what not, report Z distances relative to their "Elevation Base" setting, which is typically the Survey Point. It has nothing to do with the altitude of the Toposurface (or the Toposurface's Internal Point Elevations) in the Project

Re: Toposurface elevation measurement differs from levels

Ilic.Andrej — Tue, 02 Jun 2020 21:22:43 GMT

@barthbradley wrote:

Coordinates? I am not following you. Spot Elevations and Contours labels, and what not, report Z distances relative to their "Elevation Base" setting, which is typically the Survey Point. It has nothing to do with the altitude of the Toposurface (or the Toposurface's Internal Point Elevations) in the Project

Why would spot elevation value be different than the actual altitude? I have never seen a survey that has that kind of annotation. This is why I think that the spot elevation value should match the toposurface internal point elevation. It can be achieved only if the survey point was moved when unclipped. I guess when Revit says "Elevation origin: Survey Point", it actually refers to "Elevation origin: Survey Point Origin", not the position of the point itself.

Re: Toposurface elevation measurement differs from levels

barthbradley — Tue, 02 Jun 2020 22:39:31 GMT

It's all relative. Alternatively, the OP could model his Toposurface in a separate "Site" Project, Link his building into that "Site" Project and then lower the Building.

Re: Toposurface elevation measurement differs from levels

chhuanmawia18 — Wed, 03 Jun 2020 14:59:00 GMT

Thank you so much for the very professional video clip and explanation you ofered . Excuse me for the late follow up as i had to experiment on it for a bit before replying and also had to go to my office, In this project you explanation was quite corrrect , but i also found out what @barthbradley said about the internal origin post which the Revit software wont let you change . So , when you drag the PBP or Survey Point away from the internal origin point , you may set up the datum level at that point by 'specify coordinate point' option and making whatever line of that to be the PBP 'ZERO' . But as @barthbradley said the internal origin point wont move, the topography points still use this internal origin as their absolute orih]gin point . So , You may have to drag whatever 'PBP zero' of the elevation you have created to actually make it same as the 'internal origin zero' and therfore make it same as the level line altitude. I hope what i say make sense. In the screenshot i have done again , you can see that i have set up the foundation level to be zero and also suing the 'specify coordinatepoint' option , you can even right click on the pbp and unclip and set the elevation to zero , it will automatically align itself with this line . But when you right click on it and click 'move to startup location , it will always still go to ththe internal base point of the project( which you cannot move). So i thank you and @barthbradley alot for your discussions ...

Re: Toposurface elevation measurement differs from levels

chhuanmawia18 — Wed, 03 Jun 2020 15:01:35 GMT

thank you so much fior your help . sorry for the late follow up as i had to experiment abit and had to go to my office . Your discussion with @Ilic.Andrej really helped me out . Also , i may have found out some other important tips that you may also not have noticed and have explained in my reply to @Ilic.Andrej . Please feel free to read on it and let me know if it's correct . Thanks again