# Split ducts and different diameters

**URL:** <https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054>\
**Category:** Modeling Questions\
**Created:** [January 25, 2022, 2:36pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054 "2022-01-25T14:36:22Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![Adman110](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@Adman110](https://discourse.shapr3d.com/u/Adman110)\
**Post date:** [January 25, 2022, 2:36pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/1 "2022-01-25T14:36:22Z")

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Hi, im quite new with Shapr3D and trying to (learn) design an alternative to a duct i have. Please see the picture attached. The problem i have is i have learnt to sweep and loft, but i cant seem to make it work with my design, my plan was to do half the ducting and mirror it later .Has anyone got any ideas please?

Thanks

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/8/88ddc713971911634d2df53cd2badf025157e8b4.jpeg)

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**Author:** ![Adman110](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@Adman110](https://discourse.shapr3d.com/u/Adman110)\
**Post date:** [January 25, 2022, 2:37pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/2 "2022-01-25T14:37:47Z")

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![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/b/b98ebf217224041a744ece3ba70c974c24f88a31.jpeg)  
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<div class="post-metadata">

**Author:** ![Adman110](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@Adman110](https://discourse.shapr3d.com/u/Adman110)\
**Post date:** [January 25, 2022, 2:38pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/3 "2022-01-25T14:38:37Z")

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![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/0/026e48ee29f0b59c33e0090f96aa24a833c268f4.jpeg)

Sorry, only aloud 1pic per post

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**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:** [January 25, 2022, 5:04pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/4 "2022-01-25T17:04:38Z")

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Here’s a way that could work for you. I used **Loft** with a spline curve as a guide. If you do this, make sure the guide is connected to both circles. After the loft I used **Copy-Rotate** 180° although you could use **Mirror** as well. Then I did a **Union** and a fillet radius at the join followed by a **Shell**.

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<div class="post-metadata">

**Author:** ![Adman110](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@Adman110](https://discourse.shapr3d.com/u/Adman110)\
**Post date:** [January 25, 2022, 6:24pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/5 "2022-01-25T18:24:44Z")

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Oh brill, thanks very much. I will have a play with this.

Cheers

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**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [January 25, 2022, 10:48pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/6 "2022-01-25T22:48:10Z")

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Hi @Adman110

Just curious, what is that part for? Looks like an intake boot for a motorcycle air box.

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**Author:** ![Adman110](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@Adman110](https://discourse.shapr3d.com/u/Adman110)\
**Post date:** [January 26, 2022, 7:01am UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/7 "2022-01-26T07:01:26Z")

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Yes @NathanD, spot on. A mate of mine has asked for me to produce one as he is finding it difficult to purchase one. Its from a CCM i think.

Also, @TigerMike i have had a play and the design has come out perfectly, i will hopefully be printing the first one today.

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**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [January 26, 2022, 6:09pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/8 "2022-01-26T18:09:24Z")

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@Adman110 keep us posted, I’m curious how it comes out. What are you printing it with, material wise?

The older CCMs are difficult to find parts for, even though a lot of them used an off the shelf BMW engine.

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**Author:** ![Adman110](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@Adman110](https://discourse.shapr3d.com/u/Adman110)\
**Post date:** [January 27, 2022, 12:04pm UTC](https://discourse.shapr3d.com/t/split-ducts-and-different-diameters/17054/9 "2022-01-27T12:04:39Z")

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Yer, my mate said this part is discontinued and they always failing. Im trying first with TPU plastic but im worried about the heat from the engine, but we’ll see. Its in its 19 hr print now so i’ll let you know how it goes 👍