APPROXIMATE VOLUME FOR OPEN POLYSURFACE

Replies to This Discussion

Permalink Reply by David Rutten on July 5, 2017 at 1:03am

Is this about closing an open polysurface so you can measure the volume, or defining a new volume metric that works on open polysurfaces?

What does the open polysurface look like? I.e. what sort of holes does it have?

Permalink Reply by Firat Aydin on July 5, 2017 at 1:15am

Hey David;

The red polysurface is the excavation geometry (roughly). 
In the red surface there are many small tiny little openings and i dont know how to fix them one by one.

Yellow is the roads. they are quite smooth and i guess there are no open cavities with them.

What I am trying to do is

1) extrude yellow surface far below the red one

2) trim the yellow surface from the intersection of red. 

Then I must end up the FILLING geometry for the road. Im just trying to calculate how much soil needed for the construction.

Results are not need to be precise. 

I need some idea how to approach this issue.

Cheers!

Attachments:

• EXCAVATION & FILL.jpg, 221 KB
• EXCAVATION & FILL.3dm, 16 MB

Permalink Reply by Firat Aydin on July 5, 2017 at 7:38am

Thanks Tom;

Your tips sparked my mind and I put some of my bricks on yours.
Now the job is done.

Cheers!

Permalink Reply by David Rutten on July 5, 2017 at 7:40am

If accuracy is not paramount, then a sampling approach may work. You basically shoot thousands of lines from the road surface (use Populate Geometry to generate a good point-spread) downwards until they hit the surface. Since the surface has holes, some lines won't hit it at all, you need to remove these. Then you divide the total road surface area by the number of remaining rays, giving you the average area for each ray. This average area multiplied by the length of the ray gives you the approximate volume per ray. Add up all the approximate volumes for your final answer.

Permalink Reply by David Rutten on July 5, 2017 at 7:42am

One problem is that the excavation surface is above the roads in certain places. What needs to happen here?

Permalink Reply by Firat Aydin on July 5, 2017 at 7:48am

Yeah I know 
In some areas the excavation surface is higher than the road.
Such areas must be excavated more.
But they are not too much I simply ignored them.

Permalink Reply by David Rutten on July 5, 2017 at 7:50am

Incidentally I really wouldn't recommend working in millimetres that far away from the origin. All sorts of mathematical inaccuracies creep in when your numbers are too big.

Permalink Reply by Firat Aydin on July 5, 2017 at 7:47am

Ahh yeah you are right 
Why i didnt think that.
Sometimes my brain needs a small spark to generate new ideas.

Thanks David 

Next time i will keep that in my mind and next time I will fix such things quicker

Permalink Reply by David Rutten on July 5, 2017 at 8:00am

Attachments:

• volume approximation.gh, 22 KB

Permalink Reply by David Rutten on July 5, 2017 at 8:01am

Wait, I did it wrong. It's better if you calculate the average are per ray using the original ray count, not the reduced ray count I think.

Permalink Reply by Firat Aydin on July 5, 2017 at 8:07am

David,

Is it the filling volume?
It is not a quite realistic figure to me.
My results was around 120 K m³ 

Permalink Reply by David Rutten on July 5, 2017 at 8:18am

Also, forgot to mention I converted your geometry to coarse meshes first in Rhino. Seemed like the smart thing to do.

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