Users who do not have the luxury of the Roof Designer in AS4000 and later versions have to build up roof using the freehand roof tool, unless the inflexible bookroofs will do. It is frustrating to try to get perfect alignment with the freehand tool, and yet all the ingredients are there, if the tricks are knowm.
Go back and read up on the Punch! graphical user interfecae. Pay particular attention to the nudge and the snaps that the interface affords users. We will be using concepts from these descriptions.
Default snaps are set to one inch horizontally and vertically, and 5 degrees in angle. These are usually fine for the work we will do, but you may wish to change them for various reasons.
Walls are the foundation (pardon the pun) of the roofing system. Punch! makes additional requirements on walls that need to be obeyed. For our purposes here we will make use of a scenario submitted on the Punch! forum:
Situation: I have a fairly simple rectangle of a 4-car garage. For the second storey I want a mother-in-law centered on the garage, but set back about six feet on a side. In effect, the mother-in-law is a second rectangle that emerges out of the garage roof which is approximately 24' x 36'. Putting a roof on the second storey is no problem.
Problem: The roof on the first storey rises to meet the mother-in-law walls on 4 sides. At each of the four corners I'm having trouble connecting the four straight sides of the 1st floor roof. It looks like I need two triangles per corner to extend the 1st storey roof into 45 degree angles at the apexes of each corner.
The traingles don't really connect very well and I'm having a devil of a time making the slope correct. Is there a secret trick to this?
First, the walls. The best approach is never to allow walls to double up, so to prevent that and to allow for Punch!'s insistence on a continuous exterior wall, we'll use the WallBreak tool to make three walls out of the one existing wall that the mother-in-law will fit into, and delete the center of the three. It will be replaced later with an interior wall. Now draw the three exterior sides of the mother-in-law with the exterior wall tool and use the mouse to drag the ends into the ends where the center wall was deleted, allowing the walls to join up. That creates the exterior wall circuit including the new room. Use nudges to get all wall dimensions correct after getting them connected correctly. (Note: the user will not ordinarily see the dashed red foundation footer lines on the roof tab - I show them here to demonstrate which walls are exterior, as oipposed to interior.)
Draw in the roofs with the freehand tool, roughly. Don't worry about placement, the only requirement is to get the numbr of corners right. Adjust the direction of the down-arrow correctly, and set the pitches. On the Detail tab, create a square which is the dimensions of the soffit - in this case, we will go with a 16" soffit, so we create a 16"x16" square, and then right click on it and send it to the roof tab (It will be blue when it gets there, the color of objects on the roof tab. I have it red here for illustration purposes only). Drag the top and center roofs over so thet their corners match with the far corner of the square, while the near corner matches the outer edges of the walls. Using as high a zoom as possible will make the movements easy. This LiveView shot shows how the roofs look in 3D at this point - I colored the roof panels for easy visibility.
Once these two are correct, then move the guide to the other corner of the new room and move the remaining roof into place so that its outer corner is aligned with the guide. click on the corner of the center roof that sticks out past the guide and nudge it back to it meats the third roof and the guide corner. At this point the three roof are aligned along their outside edges. We're done with the soffit guide, it can be deleted.
Drag the middle (peak) corner of the middle roof into an approximation of its correct position. This will need to be done while holding down the Shift key, to avoid snaps. Now let's examine the situation closely.
Computer monitor screens are laid out in square "pixels", the elements of anything appearing on the screen. Since they are in a square matrix, they are very well suited to display lines and patterns horizontally and vertically. They are not do well suited for diagonal lines. Except when these lines run at exactly 45 degrees to horizontal or vertical, they produce "jaggies", places where they slip from one row to the next. In this drawings the area around the arrowhead is blown up to show how jaggies are produced. The beige lines behind are at exactky 45 degrees, and produce no jaggies. So, for the sharp eyed, jaggies are one way to assure the production of lines on even 45 degree angles.
As it happens, pitched roofs that are joined at 90 degree angles have their edges meet at 45 degrees, so viewing jaggies can demonstrate precisely where the roof edges meet. ANother thing helps: Punch! snaps rotating lines at multiples of 5 degrees from horizontal and vertical. Since 45 is an even multiple of 5, that is one of the snap rotation angles available. That means that when you move one end of a line around it will snap to 45 degrees readily, and other angles near 45 (like 40 and 50 degrees) will also be snapped to, but will result in jaggies.
So, now all we need to do is grab the center point of center roof with the mouse and jiggle it a little, seeing where the snap wants to place it, and looking at the jaggies on the resulting edge lines. We can then let it go, and it will be aligned exactly as needed. Since all three roofs meet at that point, we have a target for the other two roof to meet as well.
From this point, all we have to do make sure the peak edge of each of the two remaining roofs are aligned horizontally, and the nudge the whole edge up and donw until the edge passes exactly through the peak point of the center roof. As long as the snap grid is set to inches, and the base of the center roof is an even number of inches long, the match ought to be exact.
Once the two edges meet in the middle, the only remaining task is to move the corners so they coincide with the center point. That can be done with nudging.
Sometimes it is difficult to select the right point or edge of a roof piece due to interference from other pieces, walls and so on. Punch! gives a few "helps" to select the right point. The first is that if a roof is selected, points on that panel are high priority for the next selection. So, if you can't seem to select the right corner, click and select the outer edge of the roof you want first, then select the point. Anothr assist is provided by the arrows in the center of a panel; they are also selectable, and are usually easier to get at. Select the arrow, and then the point. Also note that the arrows are an easy way to tell which roof point got selected when several come together.
With the roof aligned, the 3D view shows it is perfect:
There are cases that are more difficult - when roofs meet at other than 90 degree angles, or when different pitches are to be matched. Other, possibly less exact, methods must be used in these cases.
 |
This page last updated on Thu Sep 08 2005 |