I.
Punch! roof panels come in two varieties: bookroofs and freehand roofs. All roof panels are a uniform 6 inches thick vertically, which is unrealistically thin for real roofs (and the real thickness gets thinner as the roof pitch increases). The top side is meant to be shingled, the bottom side is a uniform gray color. In Master Landscape Pro and later versions, the underside is colorable/texturable. The roof edges are colorable but not texturable.Each roof panel (one side of a bookroof) has associated with it a "down vector". This vector is an arrow symbol that rests at the panel's center of gravity, and gives two pieces of information about the panel: it's pitch (denoted by the numbers on the arrow) and the pitch's downward direction (also known as the angle of maximum descent). It is an azimuth, an orientation angle in the x-z (horizontal) plane.
In Punch! versions 3.5.x and below, only bookroofs are available. The gable wall extensions are part of the roof, not the wall. Asymmetrical roofs, like shed roofs, have to be constructed (including their matching wall extensions) in the 3D Workshop.
II.
Pitch -
Pitch is the common measurement of roof angle used in the US. It is the number representing the amount of rise of an angle versus the run, which is assumed to be 12, so a 5 pitch means that the roof will rise 5 inches for every twelve inches of run. Elsewhere in the world the angle in degrees is used rather than pitch. The two measurements are related by the formulas:pitch = 12 * tan (angle)
angle = arctan (pitch / 12)
angle = arctan (pitch / 12)
Despite its "english-system" connotations, pitch does have some reasons to be favored, as we will see below. It is also much favored by carpenters, because of the use of linear versus arc angle measurements. The common carpenter's square allows a trained carpenter to create cuts at any pitch desired without the need for a protractor.
III.
Bookroofs - Book roofs come in six varieties, called: gable, hip, hip/gable, hip connector, gable connector and cross connector. They are all absolutely symmetrical along one axis. Each roof has from two to four surfaces, all at the same pitch. The roofs are all rectangular (the connector parts are attached or taken away from the rectangle, but it remains); no additional handles allowed. These roofs work great when the house they cover is all right angles, and when what happens in the attic area is not an object of 3D display, because connectors do not break holes to insert themselves into a roof when meeting, so attic rooms will be filled with roof sections that normally would not actually be built. They are designed to be used when all roof parts have the same pitch (not the same direction); when their down vectors are at right angles and the pitches are the same, all edges meet at multiples of 45 degrees, allowing them to match up neatly. Bookroofs can only be edited in size, orientation and in the basic pitch. Unlike other objects, the size is changed by grasping one corner handle and moving it, changing the dimensions of the roof's rectangle.
IV.
Roof Panels -
Freehand roof panels are more flexible than bookroofs. They can be drawn in any shape - they can even be shaped into rings which capture one or more holes in their middle, allowing them to have embedded holes. Unlike bookroofs, the down vector can be oriented to any degree - it can be twisted with the rotation tool to 15 degree breaks, or Edit->Rotate... may be used to set a fine angle. [Note: version 10.0 introduced a bug that doesn't allow fine rotation of the slope arrow The PlansPlus PowerTool can fix this for user's in need.] The other two roofing tools, and the Roof Designer PowerTool in AS4000, all use the freehand roof panel to do their jobs. Punch! has given the freehand panel one other useful property: the elevation may be measured from either the lowest extent of the panel, which is the way it is with almost all other objects, or it may be measured to the highest extent of the panel. This becomes very useful when trying to match a panel up to another panel, when they meet along the ridge line. When a panel is selected the elevation at each handle is displayed; when trying to line up peaks, setting the highest rather than the lowest extent makes that job a snap (no pun intended, I swear!). The only problem with this is that if you change from, say, low to high, the elevation of the low becomes exactly the high elevation, lowering the roof by it's height. It would have been much nicer if the elevation were replaced by the computed high elevation when the change is made so the panel doesn't jump (and again, PlansPlus has a function to change ho to lo without changing the elevation.)
V.
Odd Panel Situations -
OK, roofs that are at the same pitch, meeting at right angles, create a 45 degree meet angle - well and good. But what about situations in which these assumptions are violated?First, let's consider the case where the walls are meeting at 90 degree angles, but the pitches aren't the same. In that case, we can compute the angle of the meeting of roof a and roof b by:
angle a = arctan (pitch a / pitch b)
Of course, if you have angles rather than pitches, it's a bit more complicated:
angle a = arctan (tan (angle a) / tan (angle b))
If the roofs meet at other than a 90 degree angle, the angle is increased by (vector angle - 90) / 2.
VI.
Roof Designer PowerTool - The Roof Designer in AS4000 and up makes it all easy. What it does is to create hip style roof pieces which all fit together and which accommodate the exterior walls of the house. It will handle roof parts on more than one floor, allowing for roofs on turrets, bay windows and offset floors. It will handle simple gable ends (where the gable is symmetric), but it cannot handle the exterior walls on a given level being of unequal height (that is, the tops of the walls have to coincide in elevation), except with the aforemention gable ends. It will also use a uniform eave width, so it cannot be used to create an integral porch cover over an incised porch opening in a wall - it will follow the wall rather than bridging across. In case your walls don't coincide, there are a couple of options - you can build the roofs assuming the wall heights are all lowered to the lowest wall, raised to the highest wall, or heightened to an average value. Once you've done this, then simply pushing the button creates the roof pieces on all the levels. The pieces that are used are freehand roofs, so they can be easily modified after they are built.
VII.
Converting Hip to Gable -
RB Gardener has come up with an easy way to modify the hip style roofing to create a gable end. All it takes is removing the hip triangle at the end of the roof where the gable is to be, and dragging out the corners of the sides until they form a straight line across the corners. The wall then has to be adjusted to gable style, of course. The default drag way and snaps help with that final step; the only way to drag the point is along the lines defined by the adjacent sides, and that is exactly the direction you want to go, and the radial snap will snap to 90 degrees, the final resting point. Neat.
VIII.
Shingle Textures -
Roof shingle textures in Punch! come with only a single orientation, which makes the shingles on freehand panels show properly on a roof that is slanted towards the bottom of the plan window. Unfortunately, panels (not bookroofs) oriented in other directions get sideways or even upside down shingles. Even worse, walls at angles (not oriented left-right or up-down) get shingles skewed across the bias. This is a common problem for a lot of slanted objects in Punch!, but it should not be a problem for roofs, where the downward direction of the roof is always known.A similar mapping problem shows up in bookroofs only - at shallow pitch the texture is stretched across the peak, evidently caused by applying the texture to the vertical aspect of the roof rather then directly to the planes of the roof.
These problems have been fixed in version 12.0 Punch!.
IX.
Roof Measurements - Roof measurements are wrong as displayed on the Punch! plans. The measurements along edges that are not flat show a distance projected onto a horizontal (plans) plane, not the true edge-to-edge measurement. This can be readily demonstrated by drawing a roof panel with the freehand roof tool, and observing the distance along the edge parallel with the roof's downslope arrow. Now increase the pitch - notice the measurement doesn't change even though it is obvious by increasing the pitch we've increased the roof's size. Granted that this effect is not too noticeable, particularly at low pitches, but the difference is there and should be noted so as to avoid confusion with a user of your plans. For the same reasons the edge measurements of a roof (as displayed on the plans) are also shorter than they would be is measured along their edge, the roof area figures in the Estimator are equivalently short, and the roof hole dimensions are also short, but they are not usually specified by dimension. These could impact a project if a plans user used the roof area from the Estimator to order roofing and came up short, for example.
X.
Roofholes and Skylights -
In version 10.0 Punch! has finally given us Skylights to use on roofs. The skylights still use the Punch! cliche of absolutely clear glass. They come in three standard styles - rectangular, hexagonal and circular, and the custom window utility can be applied to skylights to make any other desired shape. The sine-qua-non of the skylight is the roofhole, and Punch! is supplying a separate tool to build such a hole, though the skylight doesn't needc it - it is automatically used to create the hole the skylight rests in. No longer is it necessary to build the C shaped freehand roof described above, but the hole also works in the bookroofs, making them much more useful than they were without.Unfortunately, the problem mention in article IX above effects skylights and holes, and for skylights takes a bad form. When you order a skylight, the width and height are specified essentially the same way as they are for windows - the measurement is the opening size plus some for frame. That is not the same measurement as Punch!'s skylight size. Punch!'s size is the plan projection of the skylight; that is how it appears on the plan when looking straight downward. The difference increases with increased pitch of the roof. The conversion is:
length in Punch! = true length / sqrt (1 + (pitch ^ 2 / 144))
As a practical example, suppose you want to put a skylight with a manufactured height of 72" on a 10:12 pitch roof in Punch!. The Punch! specified height will need to be 72 / sqrt (1 + 100/144), or 55.3", for the skylight to appear correctly in 3D.
This makes specifying a shape other than rectangular painful; a circular window will look elliptical in 3D in Punch!. And don't ever try to rotate a rectangular window away from having one side parallel to the roof down arrow; it will display the window as a parallelogram.
The PlansPlus PowerTool has a rectification for this problem. You can request the the PlansPlus version of the plan display the Punch! values (the default option), or the true length of the roof edge are displayed instead. In this latter mode roofholes and skylights are displayed as they are in Punch! in light gray, while in dark blue the true perspective of the hole/skylight is shown.
