Trimble Business Center

I'm aware of the option to set rebuild method to "by user" but this does not lock the surface to a set triangulation. Essentially I'm looking for an option to create a snapshot copy of a surface that will not rebuild or need to be rebuilt if the source members/linework are changed. Please redirect me if there is a better place to post requests that can't be done in a Trimble or RPS macro. 

Could you just export as a TTM and then reimport?

Good idea Erik. I also discovered you can use the RPS "Combine Surfaces" (only selecting a single surface) which essentially makes a snapshot copy of the surface, but will not update or ask to be updated if the source data is changed. 

The offset surface TML would also accomplish this. I have used this method before. 

The challenge with Surfaces is that they are dependent on source data (if they are a TIN Model built from source data), so Locking the surface would not necessarily stop you from changing the source data in some way that effectively changes the surface model. The By User setting for Rebuild Method is a Lock to all intents and purposes, because that stops the surface from getting rebuilt when source data changes thereby protecting it against inadvertent changes. You can also use Advanced View Filter Settings and set the Surface to Non Selectable - that stops you from being able to select it graphically but not from Surface Lists etc. 

So as Pat and Erik point out converting a surface to an internal surface model that is detached from source data is the only way to achieve a Lock on the surface that stops it from changing - and currently the only way to do that is to export a TTM and reimport it or do an Offset Surface with a 0 elevation offset and that will do the same thing. We can easily create a tool that converts a surface to an internal surface if the Offset surface is not an acceptable way to do this.

You can set the Selectable Flag in the Advanced View Filter to stop it being selectable but that only applies to one view filter (not all view filters or the All Filter), and you can set the rebuild method to By User to stop it rebuilding.

Setting a Lock Flag on a surface Model would be a Trimble Requirement - they can see these posts and can determine the best course of action there.

Alan

The export and re-import as TTM is probably the best option.

With the offset surface macro you need to be careful. If you just use the surface as it was "offset" then you won't have many troubles.

But if you choose to add i.e. an additional boundary or just rebuild it by mistake it will re-triangulate ignoring previous break lines and it can happen that the result isn't identical with the source anymore. It seems that the offset surface only has the point but no break line information of the source surface.

I don't have a need to do this very often but when I have, I go about it a little different. Maybe I am sideways and somebody can correct my ways...I copy all break lines to another layer and build contours for the surface in question to some ridiculous density based on the over all vertical. ( something with a bunch of elevation at a half foot, relatively flat maybe a tenth or o-five). I now have the shape of the surface and the break lines separate of the source surface. It maybe extra steps, increases file size, but I can smash and bash on a surface to my hearts content without worry. 

I do this as I haven't always had the best of luck with the surface offset function. We had a project recently that had a lot of valley grading for drainage. Ran the surface offset for SG and then contours. The contours should overlay the design contours as it is a vertical Delta but they most certainly did not. It wasn't until the valley break lines where added at the same delta before the surface reflected it source. Mostly this wouldn't be an issue, but as an airport parking lot it was subject to FAA standards. Exact is sometimes, just good enough.

So I just looked into this and the following is true

1) When we do an offset surface, we offset all of the nodes in the source surface and we retain all of the original triangulation, however we don't lock up the original triangulation by putting internal 3D breaklines around all of the triangle faces so that they cannot be easily changed - so while you do not add any data to the offset surface you are in good shape, but as soon as you add additional data to the offset surface a retriangulation happens and that can give quite different results to the source surface (especially if it was modeled by a different system or the same system but with different model settings). 

2) When you do an offset surface and use a clipping boundary, by default the offset surface will be different to the source, because the clipping boundary breaks the triangles in the source surface along its path and those extra nodes have to be triangulated into the new offset surface - so the offset surface is different in the triangles that connect to the clipping boundary line points that were generated. There is not much that can be done to avoid that failing creating 3D Breaklines around all of the triangles in the source surface and then breaking those using the Clipping line and retriangulating in the changed data - that will always give a slightly different result because the data is fundamentally different.

3) We will look at this next week to see what we can do to make that more robust - because if you add just one point it will retriangulate all of the data and without the triangle side breaklines to stop it or having the knowledge that was used to constrain the source design, TBC just triangulates the way that it triangulates all of the nodes without the breaklines which results in a different surface model entirely.

I suggest that we will add the ability to add in 3D Internal Breaklines around all triangle sides, and that if using a clipping boundary we try to hold as many of the source triangle faces as possible and allow it to just add the extra triangulation needed around the edges to incorporate the new data.

While we are at it, I have been meaning to add the ability to define several clipping boundaries, and for each one be able to define a different offset (eg different topsoil strip depths), so that we can create a new surface with multiple areas offset to remove different depths of materials - does that make sense to people?

Alan

 

 

I suggest that we will add the ability to add in 3D Internal Breaklines around all triangle sides, and that if using a clipping boundary we try to hold as many of the source triangle faces as possible and allow it to just add the extra triangulation needed around the edges to incorporate the new data.

 

         I think the explode surface command can be used to solve this problem. It adds an extra step but I just ran some tests and if I offset a surface by 0, then explode the offset surface, then add the exploded triangles to the offset surface as members, the surface maintains its original triangulation, even when I add a new breakline or point (obviously it takes the new data into account in the triangulation as well). If I add a point or line without the exploded triangles added as members, like you said, the surface retriangulates to fill any outside edges in. So I think we have the capability to do this already but it would be nice to even have a dedicated "Copy Surface" command that has a check box for exploding/adding the triangles so it will hold its shape. This also helps those who may not realize you can "copy" a surface already using the "combine surfaces" or "offset surface" TMLs. It took me a while to catch onto that trick though others may not be as slow!   

 

 

While we are at it, I have been meaning to add the ability to define several clipping boundaries, and for each one be able to define a different offset (eg different topsoil strip depths), so that we can create a new surface with multiple areas offset to remove different depths of materials - does that make sense to people?

This seems fairly similar to the new-ish "site improvement" and "create subgrade" commands, but those are pretty "finicky" to get working properly, with all the line properties and surface members and elevating the linework and whatnot. It works great if you follow the instructions but it does require quite a few steps and there are several ways to mess it up. I'm always game for more tools, especially if it simplifies the process of creating quick and dirty subgrade adjustments.

Thanks Alan

I think that Multi clips would be awful nice.  

I think there are quite a few things in here (in the area of surfaces and surface modeling and subgrades etc that we can work on going forwards - will be in touch on that Devin).

Alan 

Alan,

I think the last option you mentioned would be a nice tool to have.

For simple sites when we don't want/have te time to use take-off tools.

It would be a great help.