Ceiling following underside of hipped roof?

[tsoutherwood]

Hi,

Can't work this out... Can I get a ceiling to follow the underside of a rafter framed hipped roof?

This is where an attic extension has been done and despite dormers, some of the sloping roof is incorpoarted into living space.

Despite giving the roof "thickness" I only realised yesterday that the 3D walkthrough shows the roof as a zero thickness surface. I can only get an idea of thickness visually if I enable framing. I tried a bodge, where I set the framing to be 100mm thick and repeated every 100mm but framing doesn't respect cutouts so me dormers go bye bye.

Any ideas - or a genuine limitation?

Cheers

Tim

[Allan Chesney]

Tim,

I am not quite clear what the problem is.  You can set the ceiling to Cathedral and set the angles the same the roof so it will follow it. That will give two surfaces to the roof that are apart.  All surfaces actually have no thickness - a wall is just two zero thickness surfaces side by side and they are only a one sided surface - the other side is invisible.  To see what I mean if you insert a piece of wall and make it very thick (eg a metre or 3 ft) and place the camera inside the wall, you will not see anything except the baseboard or cornice, as the inside of the wall surfaces is transparent.  Whether this effect is what you are talking about or not I am not sure but the Cathedral ceiling may solve the problem.  Some just set the underside of the roof to the ceiling colour and not worry about the thickness - in 3D it generally would not show unless  you cross through a wall or other surface.

If I have missed the point you may have to ask again or post the BLD file so we can see what the issue is.

Allan

[tsoutherwood]

Hi Allan,

Oh - "cathedral ceiling"?... I did try that and I couldn't get it to follow teh angles of my hipped roof. But I'll have another try...

Regarding the "thickness" of the roof, I appreciate that the insides of "solid objects" are actually hollow as far as TFP is concerned, but, in the same way that brick walls have two surfaces, and inside and an outside, set apart by the thickness, I had assumed that the same applied to the roof. In fact the "underside" texture is where the back of the tiles are, not, as I had supposed, the back of the rafters...

OK thanks - I'll try adding a ceiling.

Can a "cathredral" cope with a 4 sided hipped roof with dormers?

Cheers

Tim

[Allan Chesney]

Tim,

I have never played with dormers as they are rarely see in Australia so I an not sure how they will behave.  I suspect they will not cut through - you may have to cut the hole 'manually'.

The ceiling settings are similar to the roof, you can set the angle of every face.

Allan

[Doug.S]

Dormers are probably most easily accomplished by using another "location" for the dormer "room" and its own roof.

look here for a recent discussion/example:
http://www.cadsoft1.com/customercare/viewtopic.php?t=5352

[tsoutherwood]

Allan, thanks.

Dormers. It's because you guys have infinite land and we don't - you don't need to nonce around with squeezing every last square inch out of a property
Or that's how it looked to me last time I was in QLD - haven't seen so much space except for the Mongolian plains. It's enough to make me want to emmigrate.

:->>>

Apparantly, retro-fitting cellars is taking off in London big time, despite the obvious expense and difficulties.

Actually, we do have lots of land (England is only 7% occupied by land area), but it's because the British Government have some bl**dy stupid planning rules...

Actually, they're just bl**dy stupid, but that's another story ;->

Cheers

Tim

[tsoutherwood]

Regarding the ceilings, OK - I'll try puuting in a ceiling to match the hip angles and use a new location is that proves necessary. Thanks Allan and Doug.

I got the hang of hole cutting as I had to cut holes for the staircase. Apart from this hiccup, I'm quite pleased with my model. I photographed bits of the house and generated my own textures - it looks spot on realistic which is really useful for playing with thinsg that affect the appearance.

Couldn;t have got this far without you all - thanks again.

Hope I can start contributing soon to this forum

Cheers

Tim

[Allan Chesney]

Hi Tim,

Yes it can be very satisfying when it all comes together - especially when you use your own textures and they look right.  The results can be very realistic. Have you tried the realistic rendering yet?  That introduces a few new challenges, given there are a few lingering bugs and workarounds to contend with, but when you get the lighting right it really comes alive.

Yes Australia does have a lot of space.  Western Australia is half as big again as Queensland (2,500,000 square klm) and only has half the population. This means WA works out at 1 sq klm per man, woman and child.  The town where we live is in the hills just on the edge of Perth and the SMALLEST building block allowed in the town (and surrounding towns) is half an acre, so it is very spread out - long streets with few houses. At least you do not hear the neighbours or see them much! Certainly no need to go UP to get the living space.  Having said that we do have one of a handful of house in town with a second floor and a dormer window!  I came from Yorkshire many years ago and my Australian wife is England mad - hence the dormer window!!  You think of emmigrating to Australia - my wife is wanting to go the other way!!

Let us know how you get on with your 'virtual' dormer.  Maybe post an image if it comes out OK.

Allan

[tsoutherwood]

Hi Allan,

Ah - a Yorkshireman I spent 4 years in York at uni - marvellous place, people generally much friendlier than the south.

Tell your missus not to bother - England's very much gone for a sack of ***t in recent years. Everything's regulated[1], chav's roam the streets pulling bits off cars (that's the villages, in town you just get stabbed or shot) and half the world hates us thanks to Tony "WMD" Blair. Not that I'm bitter, oh no...

<Whining-POM-mode=off>

Back to the topic: the ceiling...total genius! The cathedral ceiling behaves just like a hipped roof, so once I had that figured, I managed to get a single ceiling to sit just on the bottom face of the rafters. Punched a couple of holes for the dormers and it worked perfectly - correct intersections with the walls and everything. I'll grab some images and post them presently.

Only weird thing about the whole roof was that, in order to get the roof to sit low (support height can't be negative) the "floor" upstairs is lower than the ceiling downstairs. This means that every element bar the roof needs to be elevated by 240mm which is where the real floor actually is. Not a serious problem - I should write this up as a workaround for the Tips section. It has been mentioned elsewhere in the firum, but I don't think it's been written up FAQ style - correct me if I'm wrong.

I am very impressed with the stair element - that was the easiest complex element to get right...

Cheers,

Tim

[1] I know, having talked to an English ex-pat who moved to Melbourne, that the ozzie government has made it difficult (impossible?) for you to do DIY electrical work. But we have to involve building control for electrics, drains, windows, external doors, insulation, as well as all the sensible things like knocking holes in load bearing walls. Of course, what happens in reality is often different... We'll need permission to paint a room next.

[Allan Chesney]

Hi Tim,

My wife is not deterred! - said that things are getting that way here too - which is true I suppose although probably not as bad in view of the much lower population.  Yes any all DIY electrical work is illegal and has been for as long as I can remember (and I have worked with the only power utility in WA for 42 years) - you cannot even replace a fuse wire or power outlet.  Other building restrictions are being introduced here too.  Sometimes even colours are restricted. On one project we were not allowed to have a coloured roof as it was not in keeping with silver roofs in the area, while in other places silver roofs are banned because of the glare into neighbouring homes. A whole lot of restrictions coming in too for energy efficiency reasons.  Where will it end?!!!

Re the roof height -  I don't understand the comment "in order to get the roof to sit low" and the workaround.  It could be because I do not work with two storey houses very often but even in the past there have been comments about moving floors/ceiling/roofs up/down etc and each time others have been involved in the answer and I have missed the point as to what the problem was.  When I have worked with a two storey place, or mocked one up to see what the discussion was about, I did not have any problems. However it keeps coming up from time to time, so I must be missing something. Maybe you can explain the specific issue and this time I may be able to get what it is.

Allan

[tsoutherwood]

Hi Allan,

On the roof - the thing is that the roof edge is lower than the ground floor ceiling by about a brick, so the 1st floor location has to be set with a corresponding floor height below the height of the ceiling below. As it's a 38 degree pitch on the roof, this is not noticeable from inside as the roof quickly clears the internal space. It just means that the "floor level" on the first floor is 240mm lower than it should be, by the time you've allowed for a floor with 8x2" timbers and the fact that it's a bit lower than it should be. It's easily fixed by elevating everything upwards except the roof, but it would have been more logical to be able to set the roof at -240mm support height. Not a big deal, just needed a workaround.

On the building regulations, it seems that the energy efficiency is causing aboatload of new regs (that's "Approved Document Part L" to the POMs, different rules for Scotland and N. Ireland. I suppose with are "lucky" in that we can undertake any works as DIY (even build the entire house) - it's just you need to involve Building Control down at the local council, which is brain damaged for putting in new windows. Needless to say it gets ignored half the time. At house selling time, you can get quizzed for paperwork. If none is present, or it's "lost" you just buy the buyer an indenity insurance policy for

[Allan Chesney]

Hi Tim,

It would certainly make it easier if you could make the roof a negative height, or allow the overhang to be negative. The latter would solve a lot of other situations. What I do to save moving floors an things, is to make a new Location for the roof, set the wall height to where I want the lowest point of the roof to be and insert it By Picking Points.

If the walls cut a hole in the roof, set the Solution Type to Ignore Next Storey.

Allan