2D mesh Fail error - Ou of memory

[damian.murlatuyls]

Hello all,

I am having a problem when generating a 2D mesh of a small model (65Km2). The 2D zone is composed by 2 mesh zones. Using bulding polygons as voids. When I generate the 2d mesh, a failure come out saying: Out of memory.

I checked the PC memory (>78Gb free); I also checked the PC performance through the task manager, and it is normal too.

Has someone expericened the same problem?

Thanks

[Duncan Kitts]

The out of memory message refers to RAM rather than disk space. Given that you have added a buildings void layer I would suspect this is due to the creation of small mesh elements. The creation of these very small elements is leading to your system running out of memory. See the two blogs below for information about small elements and how to deal with them.

http://blog.innovyze.com/2013/07/23/...o-important-2/

http://blog.innovyze.com/2014/01/13/...-experience-2/


I assume the mesh is created ok without the buildings void layer?

[Pascale Duteriez]

Hi,
I've been experiencing the same issue with a model using several mesh zones, building polygons as voids, roughness polygons and porous walls. To solve this problem I've tried and generate the 2D mesh starting with the most simple model (2D zone without anything else) and then adding each structure independently of the others.

To solve your problem you can try this :
- generate the 2d mesh without voids (as suggested by Duncan)
- generate the 2D mesh with mesh polygon A only
- generate the 2D mesh with mesh polygon B only
- generate the 2D mesh with both mesh polygons
Somehow you should find out which part of your model is generating the out of memory issue. At least that's what I did and it did work. I found out that one of my mesh polygons was not precise enough and that there were some tiny overlapping with other mesh polygons limits generating lots of small elements. In that case, you have to make sure that your mesh polygons are well define. And as for the building polygons, you should simplify them as much as possible to avoid the creation of small elements.

I hope this will help.

[damian.murlatuyls]

Hello all,

I reply this post because I am experiencing a very similar problem. In my case my objective is to mesh with two mesh zones (plus the 2d zone) and using buildings as voids.
Since I got the same error I have moved a step backwards and tried to generate the mesh only with the buildings as voids and the 2d zone. But the same error appeared.
Moving another step backwards what I have done is not to take into account buildings as voids. So a very simple 2d mesh (500m2 - 125m2). But unfortunately even so I got the same error.

Does it mean that the problem comes from the 2d zone?

The PC I am using has the following features:

Intel i7
16Gb RAM
64bit System type
Around 60Gb of free memory


Thank you in advance for your help!

Damian

[Duncan Kitts]

Hi,

It would probably be worth sending you model network, together with ground model, to support@innovyze.com.

I would guess either you have river reaches or some other network feature which is causing the creation of small elements (as described in the 2 blogs originally posted) or the 2D zone size, together with the mesh resolution are creating too many elements for the system to handle. A quick way to test the latter would be to significantly reduce the mesh resolution.

Duncan

[Kristian Ravnkilde]

River reaches can create these problems. If you have a point on a bank line very close to a section end but not snapped to it, that can cause tiny triangles. Or two points on top of each other on a line - I've found that, with no idea how it's happened. A storage area at a confluence not fully snapped to the river sections, a tiny gap between river reaches because the node isn't snapped to a point on the cross section - it's always something small and stupid! Making internal edges a lurid colour (in the Properties and Themes - Elements tab) is a good way to highlight where something odd is going on. Goo dluck

[damian.murlatuyls]

Hi,

Thank you for all your quick answers. The model itself is quite simple. No river reaches, sections or bank lines are used. In that case it is only based on subcatchments, nodes, conduits and some weirs and pumps. By the other side the DTM I am using has a resolution of 0.5m. An interesting point was that the mesh generation itself (no buildings, only 2d zone 500-125m2) took a relatively short time (about a couple of minutes), which brought me to think that it was going smooth and easy. But when loading the mesh the memory error appeared. Knowing this, can it be related to any software cache or internal ram memory limitation?

Thanks again,

Damian

[Kristian Ravnkilde]

Then it must be to do with your voids. One or more must have a small anomaly, re-entrant node, overlap, small gaps, large number of nodes (any curved lines?) or similar. I'd suggest editing them in MapInfo (snap/thin) or corresponding in whatever GIS you use, and then try again. Say 0.5m minimum distance between nodes. I'm pretty sure it's not to do with your PC.

[Duncan Kitts]

Hi,

Thank you for all your quick answers. The model itself is quite simple. No river reaches, sections or bank lines are used. In that case it is only based on subcatchments, nodes, conduits and some weirs and pumps. By the other side the DTM I am using has a resolution of 0.5m. An interesting point was that the mesh generation itself (no buildings, only 2d zone 500-125m2) took a relatively short time (about a couple of minutes), which brought me to think that it was going smooth and easy. But when loading the mesh the memory error appeared. Knowing this, can it be related to any software cache or internal ram memory limitation?

Thanks again,

Damian

I would guess it is due to memory. What version of the UI do you have (32 Bit or 64 Bit)? The 32 Bit version of the UI does have a RAM limitation, approx. 3GB, like all 32 bit applications. Can you let me know how many elements are provided in the mesh summary?