Hip rafter

I have been stuck many hours but cannot work out how to cut the angle for hip rafter in the model attached.

There is no model attached to your post.

Sorry, i just realised the model is too big, I am just working out how to send a link.


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Which angle are you trying to cut? The rafter you have roughly placed for the hip won’t fit as it is because the angle is wrong. Here I’ve moved it into place at the ridge.Seems to me the easiest thing would be to draw a new rafter as the hip rafter.

You should be modeling with the Camera set to Perspective, not Parallel Projection. That will make the modeling process easier.

I placed horizontal guidelines at the bottom edges of the rafter tails and used their intersection as the starting point to draw an edge up to the tops of the rafters. Then I completed the loop of edges to get a face.

Next steps would be Push/Pull to give it thickness and then trim as needed.

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There may be another problem. The rule of thumb in the UK is that the hip rafter should be 1.5 times as deep as the rafters it carries. It probably also pays to thicken it if the roofer is going to use it to fix tile battens to that meet on the hip.

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Thanks for pointing this out.

Thanks David, very much appreciate your help, It took me a while to draw the edges because of it being vertical and at 45degrees, Is there is an easy way to do this ? i eventually managed to do it my using the move to to copy the line and moved it up following the internal angle on the beam. Now cannot get a face so i must have something wrong ? https://1drv.ms/u/s!AgwuFP6ysOSbg4wA8P1L_VdVtSV6wg?e=To5Qgo

Here’s a nifty trick (learned from @Wo3Dan ) , first, create some guides that mark the intersection of the two roof planes. Than create a new component or change the axe of an existing.
Make sure to place the (red) axe along a known point eg. the top center along it’s length. (btw, that’s also usefull for reporting lengths etc.) In this case, the center would be the right place since it is the line that intersect both planes.
Once the red axe of the component is set, just double click to finish the other (green).
Check how the axes is set by entering the component (select, click , than Escape to get out.

Now, change the drawing axes of the model. Start to set the origin on the intersecting guides, the next click is at the corner of where it comes together. The next step is to set the green axe, but this can get tricky since we do not know or have drawn a point where it should be pointing at.

However, we know that the blue axe needs to be upwards. Check the statusbar at the bottom left, you will see that the modifier key can change the order to pick the next axe (normal: Red, Green).
So click that modifier key and we now need to set the blue drawing axe. This can be locked by clicking the Up Arrow.
Once the drawing axes are set, drag a new instance of the rafter into the model from the component panel, and you can place it on the origin:
Once in the correct position, you can reset the drawing axes or place it on the other corner first. Make them unique (rightclick > Make Unique) and start editing. (make it larger than the others!)

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I would love to see the original “lesson” that you refer to :wink: (memory loss at my end)
I know how to do this in SketchUp and double checked the construction “on site”, see: How To Frame A Hip Roof - Including A Common Rafter Review - YouTube

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Thanks for describing this trick, I am trying to follow it but cannot see how to produce the 45 degree angles at the top of the rafter Are you be able to upload the finished component to showing the new angles on the rafter ?

Create a face on the other rafters (activate rectangle tool, hover over the top of a rafter till you see a magenta inference, hold that inference with the shift key) pull it up, then sideways make a (solid) group which you can use as a cutter or intersect faces.

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Thank you @MikeWayzovski, I now remember. Part of the trick is that SketchUp uses the current drawing axes to align a new component instance picked from the component library.

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@rchwha I think it might be worth knowing that there are some small errors in your model that can cause problems as you proceed.
Among other things your common rafters are not the same thickness at the top and bottom.

I would recommend going to Window>model info>Units and unchecking length snapping. While there, increase precision to the maximum.


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Here’s a method of modeling a hip rafter with follow me and sold tools. It’s probably not what a real world hip rafter would look like but it’s a good starting point as it can be easily modified. Most builders don’t bevel the top anymore.
The .gif had to be down sampled a few times to meet the upload limit. Sorry for the choppiness.
Follow me hip5


Thanks for your help, using the rectangle tool to get a face but the angles and the birds mouth i tried to do it with several several rectangles, but cant find how to merge them ?

Component_7.skp (31.2 KB)

Dave, I cannot make a face on the rafter, if you have a moment would appreciate your help.
Modified roof rafter.skp (15.0 KB)

In order to get a face all the edges must lie in the same plane. In this case they should all have the same Y value but they don’t.

Here I’ve fixed it and can then trace an edge and get a face.

You might find it easiest when doing this sort of thing is start with a large rectangle. Draw the shape on it and then erase what you don’t need.

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