Don't worry, not getting This is after all what we made the forum for

If you're ok with the long reply times (I have job and shit), then we're good.

Hmm, facet normal problem and stitching needed... sounds to me like two different problems. The normal of a facet (facet usually refers to the surface of a single triangle in the mesh) simply means, which side of the face is up, and what is down. I believe the Triangulation process makes the normals correctly.

In case not, select the DEM, press "Tab" button (puts you in edit mode), make sure you are in "Face select mode", press "A" to select all the faces. Now look for the "Normals: Recalculate/Flip Direction" on the left side of the Blender interface. Try them and see if it makes a difference.

Stiching would, as you say, indicate that the model is not watertight. Then we need to weld vertices. Hmmm, it will require another investigation from my side, and I just don't have the time right now.

If you could manage to upload the mesh and give me a link, I could have a look at it myself. Another option is to try the DXF exporter, maybe there is a fault in the STL exporter?

Let me know how you get on.

Nighthawk

Thanks for the continued support.

I sent the file as an stl to the cnc workshop and, after opening it in Solidworks, they sent me this reply;

'Now then, there are STL face errors in your model that need stitching together (this is the area where the you will see theres a weird tower effect, as its reading the gaps in the faces).'

They also sent the attached image. You can see the towers in the middle of the valley that shouldn't be there.





I will follow your instructions again and let you know how I get on. I will also try and make a copy of the mesh available but I'm not sure how to do this as the file is 14mb.

Chris

Yes, that looks very strange indeed. Like some kind of glitch. I can totally imagine it giving some problems. Does make me wonder though, how the original ESRI file looked like...

There are different ways to upload and share files. Personally I don't use any of them, but if I should recommend one, it would be Dropbox.

Using Dropbox, you can upload up to 2 GB for free.

Nighthawk

The shapefile looks ok I think. It seems the lowest surface (lake bed) is where it's blowing out so maybe I had moved it below the mesh and it had a negative value or something. I have moved the whole model up above the mesh and am waiting to hear from the engineer if it has still got face errors.

Next couple of challenges;

a)I have imported a large area (40km x40km, 16 x the sample area I was working with) into Blender as a shapefile and am trying to triangulate it. My computer (laptop) doesn't seem to be able to cope with this. Do you think this is a limitation of my computer power? Would a more powerful machine chew through this do you think? Any work-around suggestions? Someone mentioned pyramids, whatever they are.

b)The next step is to identify where the lakes are on the DEM and lower the surface so that when it is machined out, I can inlay a different sheet material. I have vector maps as shapefiles with the relevant data on but I don't know how to select the water and then change the elevation value.
Again, advice very much appreciated.

Thanks
Chris

Hi Nighthawk. I thought you might be interested to see this. I made it with your help. Many thanks.