Trimble Business Center

I have come to use the Create Side Slope command at lot in my corridor models, especially when I have to deal with intersections and ramps thus turning them into a site model. It would be nice if Create Side Slope maintained the structure of the Master Line i.e. the created parallel lines maintained the the curve data of the original line, and populated the elevation in the vertical tab of the line string. This would aid in maintain consistency and control of the triangle density when using the lines to generate a surface.

*posted by mistake in "Trimble Business Center Group" not really sure what they do over there anyways.

Master Line / Edit Linestring / Horizontal

Master Line / Edit Linestring / Vertical

Back of Curb Line Generated by Create Side Slope / Edit Linestring / Horizontal

Back of Curb Line Generated by Create Side Slope / Edit Linestring / Vertical

So instead of chording curves etc, maintain horizontal geometry with VPI's similar to the results obtained via the Offset Line tool? I agree, this would have some useful applications. I've come to use the sideslope command quite frequently as well, but there are situations where the fact that it results in chorded geometry prevents me from using it. Usually when the derivative line will be used for staking, etc.

Maybe the sideslope could have a boolean property "Chorded=True/False" that could configure this behavior. If I'm modeling surfaces, chording can be desirable because it simplifies the surface, reducing the number of triangles generated. This is good for a machine model.

Yes, I have to create models with pretty dense triangles due to the 3D pavers and 3D concrete screeds. Mostly my issues is that I use the side slope function to merge several corridors and intersections. Compounding the issue of triangulation I am often dealing with ADA ramps and other transitions at driveways and variable widths of curb and sidewalks. Side Slope has been extremely helpful with these types of items were offset falls well short of being much help.

When the source line contains Arcs and lines only that is one thing, but an offset to a spiral is not a spiral. Similarly when the alignment has a Vertical Curve in it and the pavement is changing cross slope, computing a 3D curvilinear line is not really possible, that is why the output is chorded today because there are a lot of times when trying to just do an Offset is not really all that is happening from a Geometry perspective.

Alan

I need a bit to get back to you Alan, but I do have a few questions and your wording today has me wanting to read between the lines...

Alan, everything I work with almost never contains spirals. I think this is a regional thing.

What we are talking about already exists functionally in the Offset Line tool, so computationally it is possible. I'm not sure how the Offset tool handles spirals because I've never tried it with a spiral, but it seems like an exception could be made to always use chorded approximations in situations where computing true geometry simply isn't possible. Maybe there could be a tolerance specifically for this, separate from the "Sampling Distance" property of the template or the "Tolerance" mode of the sideslope.

Alan, I agree with Stephen, it is a rarity in my region to see spirals in alignments, most commonly I find them in rail road alignments. However, I understand that this very well may be a regional difference, but I would like to expand as to why this is a concern of mine.

Within the two enhancements I posted on the same day "Change Elevation / Surface Elevation", are both to get to the point where I can create 3D line work that is consistent and easily editable due to minor modifications throughout the life of the project. As I understand it there are basically two decent ways of creating 3D line work for a complex corridor with intersections and side streets with the goal of creating a single 3D site:

First

1. Create corridors
2. Use corridors to create intersections
3. Check node manager to ensure consistency
4. Explode surfaces
5. Use advance select, project clean up to join, and advance select to layer the items
6. Use side slope to fill in radius' cut out by intersection command
7. Repeat 1-5 for sub-grade surface

In addition to repeating this process often throughout the life of the project due to RFI's and self inflicted errors, you are also creating extremely large model with line work that the data collect can find a struggle to handle. Additionally, Trimble data collectors and machine control aren't the only items that need this information. Now we have Site Vision, Catalyst, and 3rd Party tools that need this information. Site Vision isn't an issue yet except for the people heading that product up don't understand my jokes about the repurposing of the name from the original machine control systems. However, Catalyst and TMR (3rd party robot that paints lines for us) both work better with simple 2D lines that are not coorded but rather hold radial information the coords along a length of road are too much for either the operator or the device to handle.

Second

1. Create corridors
2. Use corridors to create intersections
3. Use node manager
4. Elevate geometrically correct lines (usually PGL's and gutter or edge of pavement) to surface's. *Usually same lines used as 2D reference lines within the corridors commands.
5. Use side slope to create curbs, sidewalks, medians, slopes, and ditches. At this same stage you could also use the side slope function to create your corridors 3D line work by coping your corridors template instructions, but you run into the same chorded issue mentioned above.
6. Repeat 1-4 for subgrades

This method I find to not only be much quicker, but also requires less clean up. However, I am still up against some simple line and some dense chorded lines. It also creates an issue with machine control as the elevate line to surface command does not create nodes at each triangle, so when I use the line work to create a surface the machines to line the lack of triangle density, especially concrete and asphalt machines.