topic Re: topography mesh in Modeling

topography mesh

Anonymous — Thu, 25 May 2023 15:11:59 GMT

I have an topography mesh already created, and need to edit it to allow the footprint of my building. What is the best and easiest way to do this?

Re: topography mesh

Anonymous — Fri, 09 Nov 2007 21:01:21 GMT

With the polyline tool, draw the shape of your building footprint.
Select the mesh, select the mesh tool, move the cursor to the
edge of the mesh until you see the Mercedes cursor, press the
left mouse button to see the pet pallet, select the subtract
pet pallet item, move the cursor inside of the footprint polygon,
press the space bar, and left click. A hole will be created in the mesh.
Fill the hole with another mesh with a flat top at the elevation
of the underside of you slab floor.
Peter Devlin

Re: topography mesh

Thomas Holm — Fri, 09 Nov 2007 21:54:23 GMT

I would say it's easier to use Solid Element Operation. Use the lowest slab of you house (foundation), or draw one the size of the house's footprint,set it as operator and the mesh as target, and subtract with upwards extrusion.

This way, you can also move your house and the excavated hole will follow it.

Re: topography mesh

Anonymous — Fri, 09 Nov 2007 22:18:05 GMT

Hello Thomas,
Shouldn't it be pointed out that with the SEO method
if there are any contours in the area of the excavation
they will remain in 2D after the SEO is performed.
Peter Devlin

Re: topography mesh

Thomas Holm — Fri, 09 Nov 2007 22:35:12 GMT

True. But in my projects, they mostly get hid by the house. Should I want the terrain visible alone, I could hide the contours with a fill in front, or make the operator slab visible and turn on its cover fill. Still easier and more flexible than the cut permanent hole method, I think.

Re: topography mesh

Anonymous — Fri, 09 Nov 2007 22:45:16 GMT

Hello Thomas,
Yes you can do that. I was wondering if you often need
to drag your buildings around in a site and thus need to
use the SEO method. I suppose that if the buildings are
multi-story you would need to hide the mesh so you
could use the fat marque to drag the building without
distorting the mesh.
Thanks,
Peter Devlin

Re: topography mesh

Thomas Holm — Sat, 10 Nov 2007 11:08:15 GMT

Well, I don't often need to drag them around, but the SEO method is easier, so why not use it?

I often need to drag them around just a little in the beginning, though, when I'm working to find the exact best position for the house. How I work depends - if it's a small project I usually place the mesh on a story below the lowest house story - then I drag the mesh around, not the house. Simple and easy.

If it's a slightly bigger project, the terrain mesh and the site plan are combined in a separate pln and hotlinked into the house .pln - still I drag the mesh&site.

An even bigger project, with more than one house, might require the opposite method - the houses are hotlinked into the site .pln. Not until then I move the houses/hotlinks.

Re: topography mesh

Anonymous — Sat, 10 Nov 2007 18:41:23 GMT

Hello Thomas,
I can see the advantages of the SEO method especially
now that we have cover fills. I remember trying it in AC 8
and deciding that if you did not have to move the building
around and if the footprint was decided the cutting a hole
method was as fast especially since you had to draw a solid
white fill over the floor slab to hide the contours.
Is it your method to, instead of grouping the floor slab
and the basement walls or frost walls and using this
group as operator, you would make a special slab on
a normally hidden layer as the operator so that you
could change the walls, add walls, etc, then edit the
shape of the special operator slab? It would seem
that this way you would not have to do another SEO
every time you changed or added something.
Thanks,
Peter Devlin

Re: topography mesh

Rex Maximilian — Sun, 11 Nov 2007 12:09:12 GMT

bertoldi wrote:
I have an topography mesh already created, and need to edit it to allow the footprint of my building. What is the best and easiest way to do this?

I have TWO layers for contours: "Contours (Existing)" & "Contours (Revised)." I COPY the existing mesh to the revised layer so the original is never modified from the original survey. On the revised mesh I use the landscape consultants DWG file underlay, or eyeball it yourself and reshape the contours around the house where fill is required. THEN and only then do I create a house pad contour on the mesh. You don't want this shape to cross existing contours. In some cases the front of a building will use this method, but I do not reshape in the back. I will use SEO there for instance. So you can use both methods together.

Also, the slab doing the cutting can be from the hotlinked building file! As it changes in the building.pln file, it'll recut the site when updated.

What's nice is now you have two meshes that you can use the interactive schedule with to find the difference in earth volume.

Click on image.

Re: topography mesh

Thomas Holm — Sun, 11 Nov 2007 15:36:10 GMT

Peter wrote:
..Is it your method to, instead of grouping the floor slab and the basement walls or frost walls and using this group as operator, you would make a special slab on a normally hidden layer as the operator so that you could change the walls, add walls, etc, then edit the
shape of the special operator slab? ...

Actually, it's easier than that. In my cold country, the preferred foundation method nowadays is to cast a concrete slab on a layer(s) of insulation, usually 100-300mm EPS (extruded polystyrene) plastic foam sheets. (This gives an optimum of combined heat and moisture insulation for our climate).

Since the lowermost layer of insulation is even/level all over the foundation area, I simply use that as the operator. No need to hide it. But if I want to view the pit only, I of course hide the house.

I also often use Rex's method of separating existing and intended site meshes.

Re: topography mesh

Anonymous — Mon, 16 Aug 2010 20:21:42 GMT

What's nice is now you have two meshes that you can use the interactive schedule with to find the difference in earth volume.

This is great! Never thought of that. Do you have a way to calculate cut versus fill?

Re: topography mesh

Thomas Holm — Thu, 19 Aug 2010 18:46:56 GMT

This is great! Never thought of that. Do you have a way to calculate cut versus fill?

a Set aside (a copy of) the original unrevised mesh. Calculate its volume, using the Element Information palette, an Interactive Schedule or whatever. (Take a note - but it will not change unless there's a landslide or earthquake 😉

Now, if the bottom foundation slab cuts through the site (mesh) surface, so you have to do both excavation and padding / fill:

b Place the slab (or hidden operator). Cut the required hole / pit using SEO, Subtract with upwards extrusion with the original mesh as target and the slab as operator. (If you want more exact estimates, you might use roofs as operators as well, to cut the hole's sloping sides). Check the remaining volume, subtract that from the original's (with a calculator, not SEO), and you have the cut volume. (edited: The Element Info palette will give you both original and trimmed volume in one go, so actually there's no need for step a)

c Now turn on the layer with the mesh you revised for the house pad. Using SEO, Subtract with upwards extrusion, the original mesh as operator and the revised as target.
The revised mesh will now only consist of the fill volume, check that.
And you have both cut and fill!

It might be easier to buy and use Architerra, if you do this a lot.

Re: topography mesh

Anonymous — Thu, 19 Aug 2010 21:12:20 GMT

I think I get it. Using upward extrusions.

Subtracting the original site from the final = Fill.
Subtracting the final site from original = Cut

Re: topography mesh

Anonymous — Sat, 06 Nov 2010 17:32:59 GMT

hi... is there any way i can see my basement plan after i inserted the mesh? I have placed some walls in the basement but there is only grass visible , though i made the SEO operation ... when i navigate the building with 3d explorer,or in section anything is fine ( i can walk through the basement and see everything) but in the plan view i can't. 😕 is there anyone to help me?
thanks