Creating Surface From 3d Faces

[Alfie Overacre]

Im trying to create a surface of the attached file. However the surface keeps giving me some issues as it does not follow along the face of the object. Does anyone have advice on how to go about remedying this? I'm using Civil 3d 2019. Any help will be appreciated.

Allen Jessup

CAD Manager - Designer

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There are some modeling programs that can have vertical faces. But not for Civil work. You also can't have an undercut surface or a full tunnel. Those conditions have to be handled with more than one Surface.

Another trick you may want to use is to outline the shapes with Featurelines to control the triangulation by setting them as Breaklines. On at the top and one at the bottom of each footing. Also when you offset the edges. You'll need to offset the top in or the bottom out to prevent any overhangs.

A quick caveat - you can create vertical faces using vanilla CAD tools but as @AllenJessup says this is not allowed in the Delauney triangulation algorithm as you will have the same X/Y with 2 (or more) different Z values

neilyj (No connection with Autodesk other than using the products in the real world)

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I think the reason we have to use algorithms like the Delauney triangulation is that in Civil work the program has to be able to calculate contours, slopes, cut/fill, etc. Having vertical faces doesn't allow that. I'm sure that someone could come up with a program to deal with it. But it's easier to use a proven method.

I once talked to a person who did plume calculations for gas cloud dispersion. The software they used could accept multiple Z's for an X,Y. He said they referred to the Surfaces in civil work as "Magic carpet rides". But what is Sauce for the Goose is not always Sauce for the Gander.

I'm trying to create a surface using 3d faces that was created from another program. i want the triangles of my surface to be exactly the same with the 3d faces. I check the options maintain edges from objects, but civil 3d create some extra triangles in the interior of 3d faces and also a lot of triangles in the exterior. Is there a way the triangles of my surface to be exactly the same as the 3d faces?

My favorite trick to do this is to put the surface showing TINN lines below the 3D faces layer using 'drawing order' and do the edits until I cannot see the TINN lines anymore because they are all under the 3D faces.

This is the manual way. I'm trying to find if there is an automatic way because i think that if someone has 3d faces he has the surface. Triangles over 3d faces. in my mind simple. The other program witch create the 3d faces can easily do that

1. If you don't have a border from the other package, before you make the surface make a polyline from the limits of the triangles using "AecLineWorkShrinkWrap" and pick the 3D faces. After you make the surface, add this polyline as the border and you won't have to delete any triangles

It's becasue LINEWORKSHRINKWRAP was never designed to work with 3d objects and is a command inherited from AutoCAD Architecture (that's why it is documented only in Acad Architecture help files not the Civil 3d ones). This limitation has been logged by me as a support issue.

As a workaround try this (it works for me) - isolate and copy the 3Dfaces directly east (or north, south or west) away from the rest of the model data and FLATTEN them, do the shrinkwrap here, then move the resulting polyline back to your 3Dfaces...a bit messy but fairly quick and painless

Yeah. No problem with the boundaries. But when the OP said " but civil 3d create some extra triangles in the interior of 3d faces and also a lot of triangles in the exterior". I looked for extra triangles in the interior. In the attached image. The cyan lines represent the edges of triangle that C3D has added.

Those triangles that we are adding shouldn't change the surface at all. We only allow DTM points to happen at the vertices of the triangles. In this case it looks like there are some DTM points that happen along triangle edges. If those points are actually on the edge of the triangle, then the additional triangles shouldn't change the surface at all because they are coplanar.

Thanks Peter. They wouldn't have bothered me at all. But the OP seemed concerned. I set a style with contours and triangles visible and it looked like the surface was fine. Overall the usual good job that Civil 3D does on surfaces. Maybe we need a better way to create the boundary other than copy - flatten - shrinkwrap. But that's minor.

So the thing is i'm modelling or trying to model a toilet, but when I'm going to use the subdivision surface modifier it kind of tries to close up the toilet, well, entrance, openning, whole... How can I fix that?

Blender currently supports two modes of subdividing, Catmull-Clark and Simple. Catmull-Clark subdividing subdivides and attempts to smooth out the new faces by determining the proximity of each face to each other, thus creating a roundish shape. Simple subdividing subdivides each face, while retaining the original shape of the object.

In your case, you should probably either extrude the face further into the basin and close it up at the bottom, or extrude it and form a pipe or something out the back of the toilet if you don't plan to close the mesh up.

I am trying to build a building surface by surface. Using points as reference to create these surfaces. Somehow I get the below error:

1. Input _faces do not form a closed volume.

Room volume must be closed to access most honeybee features.

Preview the output Room to see the holes in your model.

For generating rooms by faces you will need to organise all faces which enclose the room into one list. So the input for creating 4 rooms should be a tree containing 4 lists. Otherwise honeybee does not understand which faces belong to one room.

image1304443 46.7 KB

edit:

So I found the solution.

The problem:

The exterior walls and the extruded walls (from the HB Add Subface) where both added to the _faces of the HB Room. This created an error because of the double walls.

Hi all,

I face the same problem every time my facade opening is more than 0%, but if the facade opening 0% this warning did not show up. Could you guys help me with this warning? Hereby I am attaching my file.

try 10.gh (240.8 KB)

Will the surfaces always form a closed object, say if you join with low tolerance like 0.1? You then might use the joined object as reference, after joining, exploding it again and then find the matching surfaces on the original and match their normals.

However, at this point you do not know if they are all facing inside or outside relative to the machining direction, so you would need to figure out a way to determine that. Perhaps averaging all the normals and compare the average to an outside point. If they are facing the wrong way, flip all of them again.

For models that can be joined into a solid It would be not that difficult to join a copy of the inputs into a solid and check each input if the normal is aligned with the newly created solid ( and flip if needed).

For cases with not closed input I see an option to still join into polysurface.

That new polysurface is probably easier analyzed for the normal being correct than the separate surfaces.

Once you have ensured the polysurface has the correct orientation you can do as above and check inputs against the polysurface.

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