Forums >> Revit Building >> Technical Support >> Toposurface to Solid Form

eash011

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Hello,

I am trying to create a quite complicated underground building, with tunnels and rooms. You cannot cut voids into a toposurface. Building pads and split surfaces would not work. I have tried two toposurfaces on top of another, but it does not create the effect I am looking for.

I have the idea to create a solid conceptual mass using my site, and then cut the void forms out of this. I am able to import a 3D mesh of my site into the conceptual mass editor, but cannot seem to be able to create a solid out of this, ie solid below the surface of the ground.

Any help would be much appreciated!!!

Thanks 

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Typhoon

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"You cannot cut voids into a toposurface" - That's right

 "I have the idea to create a solid conceptual mass" - use the In-Place to create your Tunnels then use the "Masking Region" tool to "Clean" the hole....

"I am able to import a 3D mesh of my site into the conceptual mass editor, but cannot seem to be able to create a solid out of this" - Because it's a Mesh, you must convert that Mesh to a solid in CAD before you import to Revit, use the LISP routine "M2s.lsp"

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Attached Files 79456_m2s.lsp

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I Hope and I Wish to LEARN  more, and more, and more.... REVIT

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eash011

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Hi, thank you for your reply! You advised: "use the LISP routine "M2s.lsp"

I don't know how to do this. What software can I do this in? My university has most of the popular software available to use. By CAD do you mean 3D AutoCAD?

Thanks 

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eash011

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Hi, I just looked on net and tried to work out how to use LSP routine. In the file, it says it does not work with  polyface entities. When I export my toposurface from Revit into CAD, it comes in as a polyface mesh.

Any suggestions? 

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eash011

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WWHub

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I really don't understand why you want to model the solid earth. There is really no exterior view of these areas - only interior. 

What is important is the surface and any structures that penetrate it or rise above it.  Spaces below the surface are modeled just like above ground.  Where structures penetrate the surface, you can use pads... but I would just cut out the topography.   In sectional views, you just use filled regions around the underground structure to the surface.

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trash201

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I realize this is an old thread, however it a problem I encounter quite often....

I am always taken back by a reply that states I don’t understand why you would want to do such and such task.  I work for a very large building group, and complex designs call for in-depth planning and analysis.  The earth in which we penetrate is a very large part of our analysis and planning efforts.  With that being said, I have fairly successfully modeled solids out of toposurfaces in a few different ways each having their plusses and minuses, and none being a quick solution.  

The first way a few years ago was to create the toposurface as normal and then cut a series of sections through the toposurface at a set distance of let’s say 10'.  Exporting these sections, cleaning them up, and finally creating an arbitrary depth in which I can create a uniform closed shape on the sides and bottom of the surface.  Importing back into revit as either profile family’s, or if using newer software the conceptual mass environment importing the cad reference into a generic model family template and retracing once again using model lines to create a closed "profile" shape (make sure the shape it is 100% without a doubt closed or it will not work, and good luck finding the faulty profile in a group of 100+).  From there you can sweep blend or create form to create a series of 10' sections of your topography with a desired thickness.  This is a tedious process and does not look the best however it is a solid work around.

I've also experimented with custom multi point adaptive components, which works great for undulating slabs however gets tricky.  I find a 3point or 4point adaptive component works best.  However you are essentially breaking up a larger surface to multiple little ones, similar to the way 3ds max or any other software will facet a curved shape to smooth it out, only you are doing this manually.  Tedious but always impressive once complete. 

I've never had any real luck exporting surfaces to autoCAD and converting objects and reimporting into Revit on any version 2008-2015 it always been an epic fail.

The workarounds I've come up with do get the job done, however some take an extremely long time and have limitations after they are complete.  If anyone has other suggestions other than "I don’t understand why you would want to do this" please share, as it is still a problem I encounter fairly often.  My experience with Revit over the past years has been if you can think it you can model it.  The big problems are, what the most efficient way is?, and what are your limitations using one family or modeling environment vs another?...

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WWHub

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Perhaps you didn't read the whole thread and that's why you didn't like the answer.   What that person was trying to accomplish did not need to be modeled and our answers were correct.

In your case, I still don't understand why you do your convoluted process except if you don't understand how Revit's site works.  Your process description is what is required as a work around... but for what?  You can easily keep track of site grading and excavations using the built in Revit tools. 

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trash201

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My apologies if the comment offended you.  By no means was it a stab at you, but a general comment as to many replies I've read on various forums which in turn offer no real answer to the original question.  The understanding of why a user may want to model the geometry under the surface is really irrelevant.  For it to be said that what the original poster wanted to do did not need to be modeled is merely an opinion on the matter.  I did read the thread many times, and yes your answer is correct in reality there are no exterior views.  However, this is a piece of software and again for analysis purposes and logistics, live client presentations, and a general understanding of complex civil projects it is a huge benefit to be able to see your structure (whatever it may be) with a 3d solid of the earth vs a section box, masked region etc.  My personal/professional use of the software does not lie in one field, but a combination.  I use the software regularly for pre-construction logistics & planning, estimating, design etc. As well as construction progress tracking and a precursor to as-builts.  These presentations and models play a pivotal role in winning bids, conveying information to clients and subcontractors, as well as our in-house estimating and engineering teams.  

But yes I do agree in most cases modeling a 3d solid of the earth below its surface is largely useless, however it is important in my case as well as the original posters case.  And yes my workarounds work but they are just workarounds, tedious ones at that.  I see no reason why a simple command to extrude a solid down from a surface is not built into the software.  I am awful at code and therefore have had no real luck with running macros.  If you have any experience using revit to model a single solid from a complex surface in a more efficient manner I would truly love to hear about it.

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WWHub

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"The understanding of why a user may want to model the geometry under the surface is really irrelevant." << This is absolutly incorrect.  Many users (especially new users) don't know all the tools available and often have mistaken thoughts about good modeling practices.  If an object never shows up in most views, does it need to be modeled?  NO.  Even if it has to be scheduled, it still does not have to be modeled.  We do a lot of hotels with furniture plans but in 99% of the time, the furniture is what we call 2 1/2 D.  2D plan and elevation only.

Section boxes are a better tool then 3D modeling that is not topography.  Sure, there are some limitations like underground (not sub-level) strutures but even those can be handled pretty well by using multiple topographies.  Try a linked site model with pads under the

subterranean areas then new topography in the main model that backfills over those areas.

In unique situations, we often find that when the poster sees other options, they change their requirements.

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