Slabs/walls ignoring terrain elevation

[MBagshaw]

Hi folks,

 

Can anyone tell me why my slab foundation seems to ignore the fact that I have placed it on an elevated terrain region? My whole property needs to be raised above the surrounding terrain by 1.4 m as it is beachfront and the local council has specified that all new properties on the beach needs to be raised due to global warming. We will be installing a retaining wall around virtually all of the property and filling it to formal level platform. The slab foundation will sit on that elevated area.

 

As you can see in the attached screenshot, any rooms I add are at the height of the surrounding terrain. How do I fix this? I have attached the plan.

49 Foreshore Drive Salamander Bay – Version 2.plan

[Electromen]

Terrain has always been a little confusing to me. See if this helps.  I selected the foundation floor area and changed the heights.  Then I selected the first floor area & change heights again.

49 Foreshore Drive Salamander Bay – Version 3.plan

[Electromen]

Building Height and Terrain Height use two different reference points as "0".

Read This

[Electromen]

36 minutes ago, solver said:

Just a thought.

 

Instead of raising the bit in the center, lower everything around it.

I tried that, but it became confusing because of the building set at "0" on the lower elevation.  The drawing shows two buildings.

It's always been difficult for me to establish the correct height of the Terrain vs the building height which is usually "0"

[MBagshaw]

Hi folks – apologies for not replying to your suggestions earlier, several moves, more discussions with architects and planners, family illness, etc all got in the way.

 

I'm still struggling with this – in fact, making no progress!

 

Electromen: I tried downloading the version of the plan you attached above, but I'm being told during the file open process that I have an older version of X8 that doesn't support some features of the file. When I reply "yes" to the question about downloading the latest version, it tells me I already have it! I then set out to do what you said you had done on my own version of the plan, but I can't figure out how to change the height of the Foundation level (in any case, I don't know what I would change it to). Of course I then can't make changes to the First floor either.

 

Full something that would seem to be a fairly simple and anything but unique requirement, this is proving incredibly frustrating! It seems so logical to me – I have created a terrain area inside a retaining wall that is higher than the surrounding terrain outside the retaining wall (3.1 m and 1.9 m above high tide level respectively). I would have thought when I create a structure on top of the higher terrain area I created, CA would put the floor on top of the terrain, not buried into it down to the height of the surrounding terrain! This must be a bug, surely?

 

 

[dshall]

1 hour ago, MBagshaw said:

..... CA would put the floor on top of the terrain, not buried into it down to the height of the surrounding terrain! This must be a bug, surely?

 

 

 

Wrong,  the building ignores the terrain.   Plenty of videos on how to understand terrains.

 

hee is a video on did on terrains a while back....   

  

If you want more vids on terrain by me,  go to you tube and type in TERRAIN VIDEOS BY DSH  

[glennw]

Mark,

There are several ways the terrain can relate to the floor levels.

I have attached a plan where the floor and ceiling levels relate directly to the terrain levels so that you don't have to do the mental gymnastics to understand how the 2 relate to each other.

Have a good look at the Absolute Elevations in the Room Specification dbx's. If desired, these settings can be specified in your floor defaults.

This method means that when you have real world levels (or even assumed datum as in your case), you can specify your floor, ceiling and terrain heights in real word heights that all relate directly to each other. 

Note that the Subfloor Height Above Terrain is set to zero - in this case the terrain levels are equal to the floor levels.

I also changed all the retaining walls to default top and bottom height which means their top and bottom heights will auto adjust as you change the terrain data. 

Using this method also means that if you place something like a slab, you can use Absolute for the Elevation Reference and that height relates directly to both the buildings levels (floor, ceiling, etc) and the terrain.

 

Hope this doesn't confuse you too much! 

49 Foreshore Drive Salamander Bay Version 2 GLENNS.zip

 

PS. I just realised that you will also need to check Automatic Footing Bottom Height for the terrain retaining walls.  

[DRAWZILLA]

two of the best , right there. Scott is the best terrain dic with person I know, thanks buddy, very helpful.

Glen is the best at everything , for sure.

[MBagshaw]

Hi Glenn,

 

I don't know what's going on with my version of CA x8. I tried loading the file you sent me and I get a message to tell me my version is not up-to-date. I accept the invitation it provides to update to the latest version, and it tells me it already is! The same thing happened with the attachment Greg sent me … oddly I've been able to load other files people have posted elsewhere about other topics. Must be something wrong with my set up.

 

Given that I can't load your file, I tried to make the changes you describe to my own copy of the file, but I can't seem to find the dialogues you describe (I probably need to mention again that I'm not an architect/designer and therefore I am an amateur at this, learning my way as I go). I have attached a couple of screenshots:

 

1.  The Normal Room Defaults dialogue
2. The Room Specification dialogue for the room shown on the plan
3. ...and the result after I had changed each of the retaining wall settings to use the default bottom and top heights. As you can see the terrain surrounding the retaining wall has now become curved and has raised up to the top of the retaining wall.
4. I also changed the Terrain to set the Subfloor Height Above Terrain to use the default (it has changed the value to 3100 mm) which has produced the only positive outcome so far – the room is now displaying at the correct height!

 

[glennw]

Mark,

 

You won't be able to open the file because it was created in X9.

Here is a copy that was created in X8.

If you have SSA you should be able to upgrade.

49 Foreshore Drive Salamander Bay Version 2 GLENN V8.zip

[MBagshaw]

Hi Glenn,

 

That was it! Thanks so much for doing this – I'll take a very close look at what you have done.

 

Cheers,

[MBagshaw]

Hi Glenn (and/or anyone else who been following my terrain dramas),

 

I think I might finally have stumbled across a simple answer to most of my terrain problems, and I thought I'd share this with anyone who is interested.

 

I took your plan, Glenn, that had solved my problem (the terrain level outside the retaining wall I need to build around virtually all of my property stayed flat at 1.7 m above sea level, and the terrain inside the retaining wall also stayed flat at the correct height of 2.1 m above sea level, were both displaying correctly). I then proceeded to move the retaining walls to align correctly with the original plans by architect produced using something other than CA – I'm not sure what – and the terrain outside the walls went haywire again with all sorts of weird effects, including rising to meet the top of the retaining wall!

 

After several hours more frustrating experimentation I tried playing around with the alignment of the edges of my Terrain Elevation Region in relation to the width of the retaining walls. When I first created the elevation region I wasn't sure whether I should align the edges of the region with the outside edge of the retaining wall, the middle or the inside edge. It turns out none of those options worked correctly. As soon as I tried moving the edge of the region slightly inside the retaining wall, everything lined up perfectly. In all of the reading I have done I haven't seen anything that talks about exactly where a Terrain Elevation Region should line up in relation to a retaining wall, but it seems now I know!

 

If what I've just described is correct, it would seem CA might have some sort of "snap to" function for correctly aligning elevation regions with retaining walls.

 

Thanks to everybody who helped with this.

 

Cheers,

[mattyt12]

Probably not the correct way to go about things but to save time and frustration in scenarios very similar my workflow would be as follows;

 

- Model Terrain as existing and not modify

- Draw retaining as subfloor walls and set top height as required

- Draw dwelling with floor level set at zero (my method I use real world elevations to AHD from the surveyor on the terrain and use the subfloor level above terrain in the terrain specification to set my floor level.

- Any sections or plans I use a cad polyline with fill to notate any onsite fill, perspective I use a slab/polyline solid or terrain feature

 

To me spending hours modelling a terrain to appear 100% correct isnt an efficient use of my time and usually causes much more frustration and stress that I can do without.

Edited April 7, 2017 by mattyt12
missed something