# Creating a 4 branch manifold with set endpoints

**URL:** <https://discourse.shapr3d.com/t/creating-a-4-branch-manifold-with-set-endpoints/40792>\
**Category:** Modeling Questions\
**Created:** [May 12, 2026, 5:31pm UTC](https://discourse.shapr3d.com/t/creating-a-4-branch-manifold-with-set-endpoints/40792 "2026-05-12T17:31:22Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Boyter](https://avatars.discourse-cdn.com/v4/letter/b/e19b73/32.png) [@Boyter](https://discourse.shapr3d.com/u/Boyter)\
**Post date:** [May 12, 2026, 5:31pm UTC](https://discourse.shapr3d.com/t/creating-a-4-branch-manifold-with-set-endpoints/40792/1 "2026-05-12T17:31:22Z")

</div>

This is my first post so bear with me.

I am trying to design a 4 into 1 branch turbo manifold for my landspeed motorbike. The end result would be printed in 316 Stainless Steel. I’ve found various tutorials online but all of them dont have fixed endpoints and seem to be made with a 90deg bend.  
My manifold has a 54deg bend between the exhaust ports and the turbo flange and each branch has a slightly different spacing between the ports.

I have scanned the original manifold so have the known endpoints for the exhaust ports and know where the new turbo flange needs to be but I am struggling to find the correct technique for creating a joining line between the 2 endpoints so I can use the sweep function. I have had some trial successes but its based on estimating where the joining line should be rather than using a proper technique.

Any suggestions would be appreciated. I’ve attached the scans, the design would be the same, I just need the single turbo flange in a different location.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/2/3/23061ee7603a46c9fc96b930e475b81e28ab6ee3.jpeg)

[https://support.shapr3d.com/hc/en-us/requests/new](https://support.shapr3d.com/hc/en-us/requests/new)

---

<div class="post-metadata">

**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [May 12, 2026, 9:24pm UTC](https://discourse.shapr3d.com/t/creating-a-4-branch-manifold-with-set-endpoints/40792/2 "2026-05-12T21:24:03Z")

</div>

Are you trying to achieve something like this?

 ![exhaust manifold](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/c/4/c4d292d2285b807fee6c53ddc63cfbc9f5e16b79.jpeg)

If so, check this out.

> [@Spline between / across front and top planes](https://discourse.shapr3d.com/t/spline-between-across-front-and-top-planes/32290/7):
>
> Hi, Here is a possible way, with splines on two orthogonal planes to define 3D edge to sweep. A few hints: you need to add the external fillets at the pipes junctions before the shell command, in order to get smooth edges inside the pipes the order of the fillets 01 and 02 is important, as well not including tangent edges for fillet 02. I started with a small radius for fillet 02 because otherwise it fails before disabling tangent edges I applied a 0.99 scaling factor to the center pipe to g…

---

<div class="post-metadata">

**Author:** ![Boyter](https://avatars.discourse-cdn.com/v4/letter/b/e19b73/32.png) [@Boyter](https://discourse.shapr3d.com/u/Boyter)\
**Post date:** [May 13, 2026, 11:14am UTC](https://discourse.shapr3d.com/t/creating-a-4-branch-manifold-with-set-endpoints/40792/3 "2026-05-13T11:14:28Z")

</div>

Thats exactly what I was looking for! I had found a YT vid showing the same technique but without the detail.

I manage to get v7 of this complete, best yet. I extract it and when the STEP file is viewed in something other that Shapr3D, it looses some of its outerbodies/shell.  
Any idea what causes that? I had something similar in a previous version but it the software it looks fine.

Thanks alot for this, I’ve been pulling my hair out for a week

 ![Screenshot 2026-05-13 at 15.04.59](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/1/4/14ea13936ad97d58e3087d9f6284f508294a3294.jpeg)

---

<div class="post-metadata">

**Author:** ![BKE](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/bke/32/31690_2.png) [@BKE](https://discourse.shapr3d.com/u/BKE)\
**Post date:** [May 13, 2026, 12:13pm UTC](https://discourse.shapr3d.com/t/creating-a-4-branch-manifold-with-set-endpoints/40792/4 "2026-05-13T12:13:43Z")

</div>

Maybe relevant,

To repair my STL, repair shops are often too limited in file size and/or are too expensive (all with an uncertain outcome).

As STL always becomes error-prone after some non-trivial work in S3D my ordinary work path is to use FreeCAD: open the file in Mesh mode (you may have to Refresh and select), then Mesh: Analyze: Evaluate and Repair. Run each step individually: Analyze—Repair, but \_not\_ Self-intersections (most typically just mangles the STL). All over again until satisfied.

Fusion is an alternative, but it typically results in the STL’s horrifying death.)

After this most SLA printer software can do the final repair step if necessary. Lychee is good at this, is free, and exports STL

My 2¢