How to "chop" remove bottom of a mesh

[rob2218]

How can I effectively take off/delete/chop the bottom of a mesh without altering the z-coords of the contours on the top of the mesh?

[rob2218]

[Barry Kelly]

You can try typing in a negative height for the mesh skirt (currently 10') - maybe -300' or so?.

You can stretch the bottom height with the pet palette but it will only go as far as the reference line - won't allow negative which is why you have to type it.

Or just place a big slab and use Solid Element Operations to trim it.

Barry.

[rob2218]

Barry!....you D Man!
lovin' the "slab" idea with downward extrusion......very clean, nice.!
thank YOU!

[Anonymous]

Sorry to jump in with a newbie question.

I'm just transitioning from revit to archicad. In revit there's a survey point and project point for associating to real world coordinates.

Is there nothing similar in archicad and an option to serve the depth of the mesh?

[rob2218]

Typically what I've done in the past is create a mesh that has "actual" vertical survey height points. Meaning...that if a survey shows that a piece of land is 900 feet ABOVE SEA LEVEl, then I create a mesh 900 feet tall so that when I tag heights using the elevation tag marker (circle with crosshairs which reads off number of the slab, mesh, or roof) it will give me the actual vertical number in feet from 0'-0"

What was happening to me was that my meshes were always so tall that when you rotate, orbit or zoom in out in the model, you always get this distorted rotational speed because the view is trying to take into account the "entire tall mesh".

So, by placing a slab under the mesh, then doing as Barry suggested, cropping or doing a "Solid Element Operation" and subtracting with downward extrution the slab...that raises the bottom up without messing with the model in 3D space (z-coordinate). it worked well.

As far as what equates to 0'-0" which then equates to a real world elevation of say.... 450'-0" above sea level? I have no clue. I've never done it that way in Archicad. I used Revit a few years back but can't remember in Revit what equals what in Archicad.

[Anonymous]

Thanks rob, that's how I'd model it i.e. with the real world/survey/os coordinates

I'm curious as in revit you can set the depth of a toposurface (equivalent of a mesh) so it's not from sea level/0 to the site coordinates.

There's also a survey point (real world coordinates in x, y and z) and project point (the corner of the building on the ground floor could be 0,0,0 for example)

[rob2218]

I think I remember that from my Revit 2014.
In Archicad, the "mesh" has depth or height but that height always reads as though it's from some vertical plane other than how actually higher the mesh needs to go.

For example, if you type "10'-0" as the mesh height, you can still move contours and nodes up to say 300 feet above that 10'-0" mark...so I'm not sure why a mesh would have a "height" needed if most meshes are all contoured in vertical Z-coordinates.

Dunno......but the solution to having a shorter mesh with the slab objects works just fine.