Just an addendum, the length of the A frame roof is the hypotenuse of the run rise triangle, hyp = (run2 + rise2)1/2.
In the case of an A frame of run = 3, rise = 6 then hyp = (32 + 62)1/2 = 6.708. a length of 6.7 will probably work. As you know there still is the problem of finding the angle of tilt. which is the method i just described. You can use a cut and try method by tilting the roof block off the end of the foundation to get an angle that looks ok.
Hi Axel5616,
This is a great question and happens to be the topic of what I'm working on right now. I have the goal of developing a reasonably easy construction workflow to get a good looking result for a roof line, roof plates and the wall fascia that go together to make an aesthetically pleasing construction.
Since I have to draw up some sketches to show the details let me answer your question in words first so you can get started on the thought process. In roof construction the key variables are called run, rise and slope. Run is the horizontal distance the roof covers, rise is the vertical distance the roof goes up at the end of the rise, and the slope is the angle of the roof. the tangent function of the slope angle is the ratio of the rise divided by the run: tan(slope) = rise/run.
For example if the rise is 3 blocks over a run of 6 blocks tan(slope) = 3/6 = 0.5, the actual slope angle is arctan(0.5) = 26.56505 degrees where the arctan function converts the slope into an angle. In the US we use a notation of 6/12 to describe this, since for odd reasons we continue to use an antiquated measurement system based on 12 inches to the foot.
On your phone you probably have a nice calculator to figure out the angle for various ratios you might want to use using the arctan or atan or tan-1 key. You will need this number to do construction. I'll show a table in my next post with pictures.
Now we get to the first detail that makes a difference in getting a smooth workflow for roof construction in Rising World. As you will notice, most of the ratios you might want to try out are almost always irrational numbers that go on forever. The question is, how accurate do you have to be? When you are in the block positioning mode there is an option to press C on your keyboard and then on the option wheel you can set the precision of the angle setting over a wide range. I have found that a setting of 0.1degree always works to get a pleasing result and a setting of 1 degree usually works over short runs.
If you have messed around with trying to do roof construction in Rising World you have probably encountered the block pivot problem. This is the issue where you want to align and position the roof plates at the right angle and place so you get the roof plates to line up with the roof fascia. The roof fascia is the triangular piece that is placed on the rise line that fits under the roof. In the diagrams I am going make, all this will be clear. The key to relatively easy placement is to develop two appropriate ridge line pieces that provide a clean look to the roof and good pivot points. There is also the issue of figuring out whether the roof extends beyond the building frame edge. This is usually done with roofs to provide better rain protection for the building sides.
By the way, in the next installment I will discuss how to get the first roof plate block on the ridgeline piece aligned correctly so that the image of the roof shingles goes down correctly, a tricky little detail... Once that is done properly on each side of the roof that side of the roof can be done lickity split.
As a preview, these three images of a test construction show some of the concepts: first image is the outside view, second image is the inside view showing beams, third view shows the block pieces which are useful for constructing roofs of various sizes for a given run rise ratio including the triangular roof fascia piece. Not included here are the ridgeline pieces .
