The TINN Model Needs to be Replaced

[Cadguru42]

The TINN model used by civil engineers was great back when computers couldn't handle much information 20 years ago, but times have changed. AutoCAD has changed. The limitations caused by the TINN model, especially the no vertical faces or hollowed out areas, are becoming much too problematic for today's needs. Since core AutoCAD has Surfaces and Solids, Civil 3D should be taking advantage of them. 

Is it not possible to use an AutoCAD surface object instead of a TINN mesh for a Civil 3D surface? Corridors could also take advantage of an AutoCAD surface and be used to create a solid when a shape is needed.

What do you guys & gals think? Should Autodesk use a more modern method for terrain modeling in Civil 3D using core AutoCAD features?

[Todd_Rogers]

You can extract 3D solids from surfaces AND corridors.

[Cadguru42]

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@Anonymous wrote:

You can extract 3D solids from surfaces AND corridors.

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I know that. That's not what I'm talking about. I'm saying the fundamental Civil 3D surface object needs to be something other than TINN. You can't create a C3D surface currently with a vertical wall in it. You can't create a C3D surface with a tunnel in it. Triangles also make for strange issues when quads should be used, such as pavement surfaces, etc. There is no way to create a "smooth" surface using triangles like a core AutoCAD surface can. 

[Neilw_05]

I would like to get away from the limitations of the TIN. Modeling walls and buildings is always a pain due to having to apply an offset or batter to the vertical faces. Using true solids would also allow for true arcs, not simulated arcs using edges of triangles. There are a host of other limitations as well. 

[AllenJessup]

Post it to the Idea Station. I'll give it a thumbs up.

[jmayo-EE]

I think it's up there but if not yes, plz add it. We have all spent a lot of time in all civil modeling apps compensating for triangle limitations.

[Todd_Rogers]

I'm not seeing it. I am waiting to give my thumbs up.

[Cadguru42]

I'll create one on the IdeaStation. 

http://forums.autodesk.com/t5/autocad-civil-3d-ideas/replace-tinn-model-with-autocad-surfaces/idi-p/...

[joantopo]

But.. is there any civil software in the WORLD which doesn't use TIN surfaces replaced for a new complex methodology?

This is my question because softwares such as Istram Ispol or Clip, both use TIN surfaces.

(The key is doing a lot of operations with surface cross sections)

[Todd_Rogers]

Maybe TerraModel? Not sure.

[joantopo]

https://knowledge.autodesk.com/support/autocad-civil-3d/troubleshooting/caas/sfdcarticles/sfdcarticl...

Solution:

To realize a tunnel or cavern in Civil 3D you have some options:

• Leave it as point cloud
• Convert it to a 3D solid or mesh object
• Create a corridor using a tunnel subassembly
• Create a 3D Solid of the corridor

Basically, the biggest issue in a tunnel is getting the extra cut and extra fill volumes using surfaces ( design surface in a single surface and another surface from a cloid points)----> solution: subassembly studio (civil+),, creating multiple shapes automatically.Then you will able to compute by shapes.

To surface section is created by importing an ascii file (offset, elevation) format.

https://civilplus.net/calculating-cutfill-shapes-in-subassemblies/

[Neilw_05]

Tunnels and other objects not handled by a TIN could be drawn with basic AutoCAD solids and surfaces and the quantities subtracted from the TIN model, but it is a convoluted solution. An integrated solution is much better. 

[dgorsman]

I suspect there's some reasons why triangles are used for the majority of work, even if quads are popular in visualization work.  I would certainly recommend against using actual solids as it isn't very efficient ie. it takes a *lot* more data to represent a 3D solid than a triangular surface (and a sufficiently detailed triangulated surface is functionally identical to a "true curved" surface, at least from the design point of view).  I'm not certain if the gains to be had in certain, narrow applications would also translate to gains in the broader use of the program or just weigh it down.

I'm not certain why Civil3D tools would be used for designing buildings as surfaces; could someone fill me in on that please?  Same thing with walls and tunnels (restrictions aren't due to triangles but how the vertices are networked)?  I'd take a serious gander at using some of the newer tools like ReMake for converting point clouds into applicable surfaces (which I believe, are also tris rather than quads).

[Cadguru42]

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@dgorsman wrote:

I suspect there's some reasons why triangles are used for the majority of work, even if quads are popular in visualization work.  I would certainly recommend against using actual solids as it isn't very efficient ie. it takes a *lot* more data to represent a 3D solid than a triangular surface (and a sufficiently detailed triangulated surface is functionally identical to a "true curved" surface, at least from the design point of view).  I'm not certain if the gains to be had in certain, narrow applications would also translate to gains in the broader use of the program or just weigh it down.

I'm not certain why Civil3D tools would be used for designing buildings as surfaces; could someone fill me in on that please?  Same thing with walls and tunnels (restrictions aren't due to triangles but how the vertices are networked)?  I'd take a serious gander at using some of the newer tools like ReMake for converting point clouds into applicable surfaces (which I believe, are also tris rather than quads).

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That's one reason why I suggested using an AutoCAD surface instead of a solid for the terrain itself. A terrain using TINN is not functionally identical to a true curved surface. Unless you up the triangles used, which increases the size of the network tremendously, to represent curves more accurately then you haven't actually made it more efficient than using just a plain surface. Think about corridors. Modeling curb returns with a frequency of 5' around the radius seems fine, except when you need to get an elevation for a handicap ramp or a drain. You have to make a specific section at those points along the radius in order to get it accurate. If an AutoCAD surface or solid was used there's no need to make the frequency hit that exact point because it'd already be there. 

No one is wanting to design buildings inside Civil 3D. We want to have buildings represented in the surfaces used for targets, which can't be done with the TINN model due to the issue of not having vertical surfaces. Because the TINN model doesn't allow tunnel like features with vertical walls or overhangs, it's a pain getting volumes for earthworks. 

Triangles were efficient back in the day when computers were limited on memory and space, but that's a non-issue now. Look at how InfraWorks can display an entire city with buildings, trees, roads, pipes, cars, etc. and still move/pan easily in the viewports. Quads are more efficient nowadays than triangles due to textures, renderings, and the video cards. 

[joantopo]

I will say otherwise:

Most of the softwares operate with a "surface sections" file, but we cannot do this in Civil 3D because the base of the data must be always a surface object. Surface sections are derived always from a surface object in C3D.

Those softwares can work with a file (ascii or binary file) which contains data about surface sections (station,offset and elevation ) format about each point. (for example a cloud points referred to an alignment).

Obvioulsy, you need an alignment to refer that data.

So, you can do operations with surface sections without having a TIN surface... (this is the key...).

This is a simple program (module on AutoCAD base):

http://www.aplitop.com/aplitop/subidas/Documentacion/TcpTunnel_CAD_es.pdf

using AutoCAD objects....  (they also use a surface sections file) *.tri