Help! 3D model not watertight / converting surface to solid / terrain modeling

[zjkaufman]

Hi all,

I am having urgent trouble with a project involving 3d modeling of terrain. This is a graduate-level project requiring ArcMap and Star-CCM+ software as well, which I am capable in, so I overlooked taking on the responsibility of modeling in Civil 3D (which I am a beginner at) and converting file formats. I was hoping one of you had some suggestions.

I am attempting to turn an elevation model of the island of Jerba into a 3D CAD model for use in computational aeroacoustic modeling (any of the typical file formats - .igs, .stl, etc. work for importing the model). I brought the data into Civil 3D 2014 as TIN Triangles, used convtosurface, and attempted to export as an igs. The export functioned but the file won't import into the other program because it requires a watertight solid geometry. I have tried surfsculpt and convtosolid as well as to create a mesh but I am sure I am giving it invalid commands because it keeps crashing the system.

Please help! This project needs to be done asap and I am utterly lost. I have attached the .dwg file I have been working in (FromIGS_WithSource.dwg). I can also give you the TIN Triangle exported from ArcMap, the original raster grid elevation file, or the non-functioning igs exported file if they are of more help — neither will attach to this message. I have access to Civil 3D 2014 and AutoCAD 2014. Please don't hesitate to let me know if there's any additional information I can give you.

Thanks in advance!

Zach

[antoniovinci]

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zjkaufman wrote:

Line_CAD file which has to be scaled x 12 for some reason

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I don't handle imperial measures, but seems kinda 1 foot = 12 inches, sir.

Somewhere, in my vintage sw collection, I think I still have an old NFR Autosurf for Dos: let me try creating an empty solid (i.e. watertight surface), and stay tuned after holidays...

[AllenJessup]

No luck this morning. I've been busy. But the two times I've tried to open the drawing with the surface I've created. I've run into fatal errors at one point or the other. I'll keep thinking about it though.

Allen

[zjkaufman]

I appreciate the continued efforts. Please do let me know though if you are able to make any progress — I have (foolishly it appears) committed to delivering this project within the next few days and need to perform auxiliary analyses on the solid model itself prior to doing so.

Thanks again,

Zach

[Alfred.NESWADBA]

Hi,

>> went back into ArcMap to see what forms I could export the TINs as [...]

Which dataset of the uploaded represents the original data?

I guess the drawing as well as the shp's are exported versions of something that was the source of all. And to avoid removing accuracy by converting data that might already be a result of something that is already converted by other software it's important now.

A second question: what accuracy do you expect/do you need to get. As we all fight against dataamount we might think about reducing geometry by doing some optimizations. If you say +/- 0.05m or +/-0.1m (or whatever tolerance you can tell us) is good enough for what is needed that might help to get a dataset that's smaller and so easier to be converted to solids.

- alfred -

[zjkaufman]

Thanks for your input, Alfred. The original data is in ArcGIS raster format, read as a single dataset inside ArcMap but stored as a folder of 5 .adf files that I have archived and attached (also available in the google drive linked to earlier). Accuracy is a secondary concern at this point, as this is more a proof of concept exercise. In generating TINs to this point, though, I have set the +/- to .25 m. Do you think it's worth generating datasets with even less accuracy to see if the system can handle them for some of the methods previously suggested?

[MikeEvansUK]

I have been looking and thinking about this one.

Firstly you can use the region command as previously sudgested then export as Acis Sat file.

Import into 3dSMax, select one of the poly faces, edit the sub entity and attach everything, next convert to editable mesh then export back out as 3d faces. Now you can build a surface you can attack the next step.

Secondly when you say a watertight solid I'm still not sure what you mean. Perhaps again you can extrude the faces in Max in the negative direction to generate a useable object. I have no idea on this one.

[Alfred.NESWADBA]

Hi,

I tried the 3DS-Max way too, the problem is not building the regions, the problem is also not extruding the regions, the problem I have is the step with unifying the extruded regions together to one big solid.

- alfred -

[MikeEvansUK]

See original posting. Import the regions to max. Then select one. Enter sub entity mode then scroll down to add. Click the selection box and select all.

This will take some time but once finished convert to editable mesh and export to 3ds file.

Reimport and you'll have a single object of faces.

This will be a surface in autocad, a solid requires a volume. So if you need a solid then back to max.

Edit sub entity polygons or faces and generate faces to close to a solid below the surface.

This may work but I have no idea. Key is in import to spec the setting so they weld.

You can then use the converttosolid command (3d workspace) to hopefully generate a solid entity.

Hopefully this will do as required.

[Alfred.NESWADBA]

Hi,

I got one result, based in the ADF, created a C3D-surface from that, cleaned up 3D-Faces by point-cleaning (twice passes with each having a max elevation tolerance of 0.125m). From that extracted 3D-Faces, converted to regions, extruded with option direction, unified them and cutted all to a base-elevation of -10m.

I can't guarantee anything, please understand that .. with that amount of data I have not enough time now to check every single triangle exported from the surface, so please verify my result with your surface, also verify that there are no holes (if so the exporting of triangles from the surface might have missed some, but even if there ar a few faces missing you can then easily built a 3D-Face at that postition, extrude it to -10 and unify that with the rest).

Hoping that is all ok now for you, it can be downloaded from >>>here<<< (12MB, will be deleted after 7 days from now on).

- alfred -