Joining extruded pipes at an angle

Hi, I’ve been having a hard time trying to get the two pipes either side on the the top flange to flow through. at the moment ts just joined up and created a surface. Any suggestions on what to do? manifold sc14.skp (934.9 KB)

Part of the problem is you’re missing some needed faces on the interior of the outer pipes.

I would redraw those pipes.

Even with the the junction of the pipes cleaned up, your component will not be a solid because there are areas inside the top flange that are only one face thick.

Also, make sure you stay on top of face orientation. Most of your model shows reversed faces. The back (blue) faces should kept to the inside.

In Addition to Daves suggestions some Problems of this model…

I think the main problem you’re having goes back to when you created the circles that are used for the extruded pipes. While generally not important, the orientation of the circles impacts how the surface polygons are aligned when you later perform the intersection. The video below shows the result when circles are created along one of the primary axes. Note how the polygons exactly line up with each other:

Your circles look like this (excuse the large image, but I wanted to show the detail):

I don’t think it matters, but I always set the precision to as small a number as possible and turn off Length Snapping:

In addition to the suggestions DaveR and Cotty made, I would also recommend keeping things in groups. I initially tried creating this using both the inner and outer surfaces as an extruded doughnut, but when I got around to intersecting them, I couldn’t tell which was which when cleaning things up. Putting the inner and outer surfaces in separate groups allowed me to intersect them more easily. Another note, if you’re using the Follow Me tool to extrude these: if the path starts or ends with a curve, the end(s) won’t be what you would expect; it will be perpendicular to the last segment of the arc which is typically at an angle. In your case, I added a straight line at end end of the curves and then trimmed off the excess. Also, using typical wire-frame logic, the inner surface runs from the top of the exhaust flange to the bottom of the header flange. The outer surface runs from the bottom of the exhaust flange to the top of the header flange. I’ve attached my model; if you explode everything, you should be able to group them back as one unit.

manifold sc14_jim.skp (1.4 MB)

[added 13h later] I can’t seem to get SketchUp to recognize this as a solid, but MakerBot (exported as a STL file) and Shapeways (exported as a DAE file) don’t seem to care.


Here’s a stab at the thing. I have no idea what the ports should look like but it can be cleaned up to produce a solid.
Interestingly, intersection work a bit better than solid tools on this particular model.



HI all, Thanks heaps for all the help :slight_smile:

Hi Shep, how would i go about making those ports collect into a rectangle of 100x50 and then inserting a radius down to the pipes? similar to what you have there but merging to a rectangle? the model is currently at 10x scale.

Thanks again


You can find examples on the forum of transitions made with plugins like curiloft.
Push/Pull Round to Square
Perhaps if you had an ellipse similar to the one in my effort, and loft a transition to a rectangle, you’d have a starting point for what you need.
The bit that I did there in the middle was just hand stitched with the line tool.
I’m sure there are others here more skilled in these “organic” shape than me.