Trimble Business Center

In TBC 5.0, while using 'Create at Intervals' command along an alignment, in certain locations two points are created within 0.004 ft of each other and not exactly on the alignment line. It appears that the "double" points are created on curves at full intervals but not at half-intervals (looks like TBC creates extra points along curves at half intervals). Is this somehow related to the function that automatically creates points at alignment transition points and why the points aren't located exactly on the alignment line?

It could be that you have a Non Tangent alignment element -ie there is a small deflection angle between the two elements and that will have this effect. In the Alignment Editor if you Hold CTRL and then click the Settings button, it will show you the Deflections in the Alignment - check that to see if these extra points are being created at those Non Tangent locations. If not please VCL out the Alignment and Points that you created that exhibit the problem and I will take a look. Also sometimes when you create a PI based alignment where there are back to back curves, the tangents may overlap slightly and we will insert a short straight between the two Curve End Points and that could also be what you are seeing. I will check on a true alignment and see if IO can reproduce what you are seeing, however my guess is that this is data related.

Alan

Here is the file for you to take a look.

Garrick Raczek

Also when you say they are "Not on the Alignment line" if you are referring to the Graphics of the Points and the Alignments not being coincident - that is likely a Graphics issue - when you zoom in tight - the alignment is always displayed chorded, and sometimes the chording will make it look like they are not coincident - the only way to check the offset is to use Explore Object and see if the offset is anything other than zero - because you cannot 100% rely on the graphics for these types of check.

Alan

This is happening not only on curves, but also on straight line, so chording shouldn't be a factor, right? Anyway, I used the Measure Distance tool before and it was showing 0.004 offset. Explore Object shows 0 offset.

Garrick Raczek

Garrick

The issue is that you are generating points along the alignment at 60' intervals which is actually all the HAL Points, all the VAL Points and every 60'. In this alignment, if you change your Project Settings to show Station Precisions to e.g. 5 decimal places you will see that e.g. the VAL has a Grade Break at 299.9957 which is one of your "Duplicate Points" and then your Interval generates a point at exactly 300' 

We have a "Point Tolerance in TBC of 1/10mm (0.000328') which if the points were computed less than this apart we would have ignored one of them, however because they were 0.0043 apart, they are considered as different points and both are retained. 

I had another question the other day on something similar and I am putting a request in to modify this command to allow 

1) The selection of Create HAL Points Y/N

2) The selection of Create VAL Points Y/N

3) The Creation of Interval Points Y/N (Define the Interval)

This would then resolve this issue because you could deselect VAL Points to stop them from forming. I don't think we want to use Point Tolerance as a Control here (i.e. If two points are closer than XX.XXX then do not create them), because then we have to have a Hierarchy of which points win over others (i.e. Intervals win over HAL or vice versa which adds more complexity to this computation / report / point generation process.

You can also run the "Merge Points" command on this data to find the "near duplicate points" and decide what you want to do with them.

The VAL is the main cause of your issue on this data and the fact that we are creating points automatically at all of the VAL locations without giving you any control over that.

You could delete the VAL or create a Copy HAL and delete the VAL and then use the Copy HAL only to get what you need.

Hope that this helps

Alan

Alan,

My grade breaks are actually at 50' intervals and when running "Create at Intervals" command I used 100', so technically, these double points should be created every 100', which is almost the case - for some reason TBC didn't create double points at 100 and 200, and then at 1200, 1300, 1400. And when TBC creates points that fall on the same station it doesn't like it and puts them 0.004' apart. I ran Point Comparison Report and the horizontal offset in all cases was 0.004.

But you're right, the issue comes from the overlap of VAL and Interval points. When I got rid of unnecessary grade breaks and left only the VAL points essential for alignment geometry (which don't coincide with the 100 intervals) and ran the "Create at Intervals"  command again there were no more problems. Thanks for your help in understanding the issue.

As a side note, while working on this, I noticed that at very tight close ups, less than 0.01 ft per inch, the Point Snap stops working, and probably because of priority, prevents other snaps from working as well. When Point Snap is turned off, the Intersection Snap for example, works fine all the way to the max zoom. None of this has a major practical impact on my workflows but it might for people that will be building our next LIGO facility, or something like that.

Garrick Raczek

I have just tried Point Snap in 5.1 pre release and I got all the way in to this resolution (the end stop of zoom) and Point Snap was still working - I also tried in 5.00.02 and saw what you saw - so it has been fixed in the next release already

It could be that some commands work better than others of course - so would be good to know which commands specifically you were running when this was an issue - I used Linestring and Polyline and they worked OK - I turned off all Snaps except Point Snap as well to check that Point Snap was the only thing that could work to make sure and that may also have an impact of course.

Alan