Angled Roof

[WhisperingPond]

I rarely use an angled roof because it takes too long to level it off, so I'm finally breaking down and asking for help. I've solved my issue good enough for now, but I know it's not perfect. 

There must be a math answer to my question. 

I used triangle prims on top of outside wall prims to support an angled roof. I've had a beer or three in case this doesn't make sense. 

Based on the dimensions of the triangle there must be an easy way to figure out the rotation of the roof that goes on top. 

Thanks. I'm sure the answer is simple. But I'm still stuck in RL thinking. 

 

[LittleMe Jewell]

22 minutes ago, WhisperingPond said:

I rarely use an angled roof because it takes too long to level it off, so I'm finally breaking down and asking for help. I've solved my issue good enough for now, but I know it's not perfect. 

There must be a math answer to my question. 

I used triangle prims on top of outside wall prims to support an angled roof. I've had a beer or three in case this doesn't make sense. 

Based on the dimensions of the triangle there must be an easy way to figure out the rotation of the roof that goes on top. 

Thanks. I'm sure the answer is simple. But I'm still stuck in RL thinking. 

 

I'd suggest you ask this in the Building & Texturing sub-forum, under Creation.  Some of the builders only pay attention to the sub-forums in the Creation area.

[ChinRey]

Just now, LittleMe Jewell said:

I'd suggest you ask this in the Building & Texturing sub-forum, under Creation.  Some of the builders only pay attention to the sub-forums in the Creation area.

Yes, that's a good idea. But no need to repost there, just report the post to the moderators and ask them to move it

[ChinRey]

  

56 minutes ago, WhisperingPond said:

Based on the dimensions of the triangle there must be an easy way to figure out the rotation of the roof that goes on top.

I assume you're talking about either a shed roof or a gable roof made from two prims, one for each side?

If so, there are plenty of online trigonometry calculators that can help you.

I suggest you make the triangles from tapered cubes rather than pathcut ones or prisms. Pathcut prims used this way will never quite fit the wall they're on top of becasue of some weird rounding errors and prisms are hopeless both when it comes to precise fitting to other prims and calculating actual size. The only downside with tapered cubes is the UV mapping and that's easily fixed using planar texture mapping.

I'm not sure if you need more help than that but just in case, here are two examples. This for a gable roof, triangle made with 100% x taper:

X size 1 m, z size 0.5 m.

The size of the legs for the right triangle are z size and half the x size, so both 0.5 m. Enter that into the trigonometry calculation of your choise and you get an angle of 45 degrees.

Here is the same triangle but with top shear to make only one sloping side:

In this case the two legs of the triangle are the z and x sizes, so 0.5 and 1 m. Enter those values into a trigonometry calculator and it will tell you the angle is 26.565 degreees.

Of course, some people will tell you that using a calculator is cheating but don't worry, we won't tell.

---

Edit: Perhaps I should have mentioned the old "parallel twist" trick?

Like this:

• Pathcut 0.0 and 0.5 for a gable roof, 0.0 and 0.25 for a shed roof
• Hollow whatever you want for roof thickness
• Twist: both Begin adn end at 45

This shifts the axises for the prim from the sides to the corner so you can simply adjust the height by changing the x dimension and width by changing the y dimension, no need to do any math at all:

Edited August 17, 2020 by ChinRey

[Bree Giffen]

I found a nice simple triangle calculator

https://www.calculator.net/triangle-calculator.html

[Lindal Kidd]

The only drawback to Chin Rey's hollowed out roof prim is that, if you try to save land impact by making its physics type "Convex Hull", you can't get into the attic...and possibly parts of the floor below.  Two prims are fussier, but don't have that particular issue.

Edited August 17, 2020 by Lindal Kidd

[WhisperingPond]

Not a typical roof for a house. Just one slanted roof. Never mind. I found an angle calculator app for my phone. It's all good now. Thank you. 

[Lindal Kidd]

Ohhh, a shed roof!

Why didn't you say so!? 😃