‘Transition between two different surface targets is not supported yet’

[soonhui]

In a nutshell, this is the problem:

Here's a drawing file.

1. From the feature lines created, I have used ‘Grade to Surface’ to have slopes of different ratios. 
2. After grading, I used the Grade Transition to connect these slopes of different ratios.
3. However, the transition was not able to be created at one end of the platforms (Refer to Image 1) which I will get an error ‘Transition between two different surface targets is not supported’
4. In this drawing, there’s only one surface that can be targeted, so how come the grading created by the program is from two different surface targets?

[ecfernandez]

Hi @soonhui, I think I get your point. You do not need transitions to achieve the result I saw you want from other transitions at the same grading (see image) 

According to what I saw in your file, you have a vertical slope (0.1:1) and a normal fill slope of 1.5:1.0, and what you want to do is close the gap that there is between them. You don't need a transition to do that.

1. Create the vertical and the normal slope until the yellow and purple limits, respectively.

2. Create a feature line that goes from the end of one slope to the other

3. Capture the elevation for the previous feature line from your terrain surface (if necessary)

4. Use a Grading Infill to complete the grading 

if you want more detail, you can draw an additional feature line here

In this way, you can close those gaps without relying on transitions, which might or might not work well. I attached the file so you can check it.

I hope this helps. Best regards

[Neilw_05]

Likely the software is confused due to it not being able to solve the grading due to the sharp bend in the geometry. Try pulling the grading back from the bend and see if that helps. Another option is to soften the bend with a radius or reduce the angle a bit. If all else fails, then use the solution suggested by Mr. Fernandez.

[soonhui]

@ecfernandez , I appreciate your workaround, but my point is not so much to do the design, but writing a script ( in C# via C3D plugin) that can do that.

So I need a simple, dumb and repeatable process that can be applied over and over, without human intervention and workaround. And the transition is a simple enough command that can be repeated across different surface, if it works. Alas that's not so.