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Query point cloud boundary then add all the points whtin the boundary

19 REPLIES 19
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Message 1 of 20
wang890
1223 Views, 19 Replies

Query point cloud boundary then add all the points whtin the boundary

i need to know if there is any way to control the points in the point cloud.

 

1. either only import the point cloud in a polyline area i specify

2. add all the points within a boundary not limited to the pointclouddensity = 100, freaking default is 15 almost cost my job today. extremely stressed out right now.

 

i am talking about extreme lidar surveys. 1km 1km LAS/0.5m contours/xyz files times 355 of them. covers a 2km wide corridor. but i only need 100m wide after i define the road alignment. no need to have all the extra points.

 

right now i densify the heck out of it and end up like 5-12m points. decent but not good enough because the geotech is bitching about that accuracy is not good for some feasibility study.

 

or is there any software i can do this besides civil 3d.

 

what i want can also do is automate the 'add points to surface" under point cloud and have the software do multiple boundaries without having me baby it over the night. right now every click is 5 minutes and adds like 400k to 1 million points.

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
19 REPLIES 19
Message 2 of 20
mathewkol
in reply to: wang890

Know that surfaces created from point clouds are limited to about 1.5M points regardless of the setting for point cloud density. At least, this is what I've been told; nobody from Autodesk has given me a direct answer though I have asked.

You can speficy a polyline as an import boundary during initial point cloud creation. Look a little harder in the wizard.
Matt Kolberg
SolidCAD Professional Services
http://www.solidcad.ca /
Message 3 of 20
BrianHailey
in reply to: wang890

If your "point cloud" is a simply xyz file, just add it directly to your surface as a point file however, before you add it, define a polyline where you want the surface to have data and add that as a "Data Clip Boundary" prior to adding the data. This acts as a filter as the data is added to the surface, is the point within the boundary? If so, add it to the surface. If it isn't, skip that point.

Brian J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 4 of 20
wang890
in reply to: mathewkol

hi Matt

 

1.5 million limit "per run". you can keep adding them.

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 5 of 20
wang890
in reply to: BrianHailey

good idea i can give this a try.

 

we have LAS and xyz. LAS i know has it all. but xyz not so sure. tried work computer can't handle xyz left it one weekend and came back monday and crashed.

 

didn't know what that data clip is for. something new to learn is good. never had to use it because the size was ok before

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 6 of 20
wang890
in reply to: wang890

does anybody know if the "pointclouddensity" variable affect the data which has already been added to the surface?

 

say you set to 15% and it added some points to the surface but at 100% it will have a whole new set of points added in. does rebuild the surface help?

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 7 of 20
tcorey
in reply to: wang890

If you change the point cloud density, the surface will not indicate Out-of-date, but it will add the additional points if you rebuild. I'm not sure why the out of date indicator does not display.

 

Also, BrianHailey's advice should be heeded, although you should know that you can use a data clip boundary with either the external point xyz files or with points from point cloud. Draw the data boundary, create the surface, add data clip boundary before adding the cloud points to the surface.

 

If you have a choice of using the LAS to create a cloud and then adding that to the surface vs. using the xyz files to make the surface, use the xyz files. That keeps you from bogging AutoCAD down with a point cloud. The less you have inside the drawing file, the better (meaning faster.)

 

Good luck with your project,

 

Tim

 

 

 



Tim Corey
MicroCAD Training and Consulting, Inc.
Redding, CA
Autodesk Gold Reseller

New knowledge is the most valuable commodity on earth. -- Kurt Vonnegut
Message 8 of 20
BrianHailey
in reply to: tcorey

Another reason to go with the raw data rather than creating a point cloud is you will get a lot more data in your surface. A point cloud will only add about 1 million points to your surface. In this day and age, (I personally have 32 GB RAM on my system), 1 million points is childs play.

Brian J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 9 of 20
wang890
in reply to: wang890

you know what you are right.

 

i just tried some stuff which takes forever and crashes on the crappy 2.4ghz dual core xeon with 8gb ram on my awesome 3930k oc'ed to 4.5ghz.

 

something 5 minutes takes 5 seconds. things that can't rebuild will rebuild no crashes. there it proves that you need a computer that is decent to run civil 3d. the bigger company i go the crappier the computer gets. weird eh?

 

if i can get a week work done in a day on a faster computer you know something is wrong with the IT department.

 

i should take over. seriously learn what's going on with hardware first.

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 10 of 20
Neilw_05
in reply to: wang890

I am pretty disgusted with the point cloud utility for building surfaces. In my experience I have not been able to get it to utilize 100% point density regardless of the Density Display setting.

 

http://forums.autodesk.com/t5/AutoCAD-Civil-3D/Clip-or-filter-point-cloud/m-p/3144490/highlight/true...

 

The way I use it is to first build a cloud (which takes forever), then display it at low density to determine it's extents. Next, layout data clip boundaries within the extents. Finally, create empty C3D surfaces, apply the clip boundaries to the definition (do this first!) and add the points from the .xyz files. This is the only way I have been able to get 100% fidelity from the source data.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 11 of 20
BrianHailey
in reply to: Neilw_05

That's the only way I know of to do it as well. Problem is, if you have a .las file, you can't add that to your surface as a point file. There's probably some sort of file converter out there that could get it in a usable format though.

Brian J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 12 of 20
wang890
in reply to: BrianHailey

we have both las and xyz.

 

the problem is total 5 billion points covering about 2km x 320km.

 

so i need at least 200m wide. length is the same.

 

which still makes it 500 million points. i just spent a few hours on my fast machine and found out that even for this computer limit is 10 million. it's not out of memory. just when rebuilding it will be fatal error. so i had to make the surface into 2. about 5 million per surface. and points is still 5-15m apart. there is no way due to software limitation i can get the true fidelity because those points are around 0.1 to 0.5m. we have to admit it, that the survey crew set the machine to too fine a interval. i prefer to have set something like 1-5m which is much more manageable for consultants. i heard some GIS program are much more powerful. would be nice to use those in conjunction which is like just get that program to export smaller point files covering say around the alignment and then just import for each exercise based on alignment left and offsets, say 100m each side. it's not going to make too much difference on the volume calculation once the surface is dense enough like now. before i had like 40m points those are no good. now i increased the number of points by 5-7 times. good enough what do you guys think?

 

this is the longest road project i ever worked. before even mountain high like sea to sky highway we were only doing 5-10 km and surface is 1m points surveyed properly by lidar. that was smooth also was using LDD at the time.

 

nothing this size. super stressful job i did all the road design and most of the drafting plan profile by myself. took me 2 months. over 300km long road with over 1400 horizontal curves and vertical curves in crapp north canada area. the ground looks like another planet.

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 13 of 20
Neilw_05
in reply to: wang890

With that much data you really need a robust decimation tool. It will cost you a little but it should pay for itself in a short while.

 

Try a web search for point cloud tools.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 14 of 20

There is a converter.  We use FME from Safe Software to convert lidar data files to xyz files.   It will let you extract points based on clipping boundaries and lidar classifications.  The resulting ASCII file can then be imported directly into the surface model, without having to use point clouds in Civil 3D.

David Zavislan, P.E. | Wood Rodgers, Inc.
Message 15 of 20
wang890
in reply to: david.zavislan

thanks everybody for your input.

 

i did a 13km comparison on the volume from point clouds after many "add points to surface" runs and end up like 5m average points spacing. about 1 million points / 10km x 2km surface. compared to the 0.5m contours from some GIS program surveyor used to generate these contours which considered every single point i think. volume difference is 0.15%. now that's enough to convince geotech that there is NO difference on accuracy. before compared only 1km every 50m with a not so dense point cloud surface and difference is like 10-15%. i guess from statistical point of view more sample represent more accurate result. i told them in the first place when you look at the thing as a whole won't make any difference.

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 16 of 20
wang890
in reply to: wang890

i created another point cloud data base only on 50km long surface x 2km and set density to 100% but now come when i draw a box of 6km x 6km and ask it to add points and only give me 120k points? total real points is 60 million. what is controlling that number?

 

would be nice just to have a function like add points to surface and use selectible number of points. 1 million, 5 million, etc.

 

i have nother area when i use same box and it gives 600k points that's decent.

 

also when you make another box differently slightly does the software will add different points? makes sense each boundary you pick if the next one is the same location perfectly on 4 corners will produce the same points. are those points selected by random or software use stastics to calculate which point to add?

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 17 of 20
Neilw_05
in reply to: wang890

i created another point cloud data base only on 50km long surface x 2km and set density to 100% but now come when i draw a box of 6km x 6km and ask it to add points and only give me 120k points? total real points is 60 million. what is controlling that number?

 

See the link in my reply on 11/12. Thus the recommendations in this thread to not use point clouds for surface models.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 18 of 20
wang890
in reply to: Neilw_05

hi Neil

 

i think i found a better solution. it's a "trick"

 

i noticed this by accident. my last post when i said it's not giving enough points? that point cloud is the original one which used LAS.

 

what i did is i made another drawing, and then i create a new point group from the .isd file. with this point cloud, it behaves differently. i am able to add 1 million points each run. problem solved. still not 100% but much better than doing 100k points at a time.

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19
Message 19 of 20
Neilw_05
in reply to: wang890

what i did is i made another drawing, and then i create a new point group from the .isd file

 

What does this mean "i create a new point group"? Are you creating Civil 3D points?

 

It would be helpful to know why there is a difference when you use the .isd file. Can you verify that it contains the same data?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 20 of 20
wang890
in reply to: BrianHailey

a new point cloud object i mean. in the new one use isd instead of browsing all the LAS again. 

 

that point cloud from isd file somehow if you look at the property has a "displayed points" much larger than the one created from LAS. i am not sure why but worked for me. 

 

i didn't need to create the boxes for add points to surface so small that i have to do many times. 

 

try it out and see. take an isd file and make a surface even you use the from point cloud extent it will give you around 1 million. but the las point group one will give like 100k. something to do with bug 

Stantec
Dell Precision 5530, Prism M320PU, C3D 14/17/19

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