topic Re: problem of maintaining a volume during a loft in Inventor Forum

problem of maintaining a volume during a loft

Anonymous — Fri, 08 Jun 2018 19:31:59 GMT

Hello everyone,

i'm troubling with a design. I'm making a rail in with a guide must pass. The problem is that the space in with the guide is supposed to go is not the same all allong my trajectory. I have a about 2 or 3mm error and i don't understand why...

thank you for your help é_è

kelly.young has embedded your images for clarity.

Re: problem of maintaining a volume during a loft

TheCADWhisperer — Wed, 06 Jun 2018 12:37:27 GMT

@Anonymous wrote:
... i don't understand why...

Can you attach your *.ipt file here?

(I suspect Loft is not the tool I will use to fix the geometry.)

Re: problem of maintaining a volume during a loft

johnsonshiue — Wed, 06 Jun 2018 15:43:23 GMT

Hi! Like JD said, it is better to attach an example here so forum experts can comment further. Did you use Center Rail option in Loft? If the start and end profiles are proportional, I would use guide rail Sweep instead. Please attach the file here.

Many thanks!

Re: problem of maintaining a volume during a loft

Anonymous — Thu, 07 Jun 2018 08:03:27 GMT

this is the .ipt !

Re: problem of maintaining a volume during a loft

Anonymous — Thu, 07 Jun 2018 08:16:50 GMT

i'm struggling with the upload of the .ipt... it dosen't work when i try to upload it in my reply 😕

Re: problem of maintaining a volume during a loft

Anonymous — Thu, 07 Jun 2018 08:24:41 GMT

@johnsonshiue: I can't use sweep because of the mouvement I want to create. I tried to use sweep before but the joint between two sweep was not acceptable. And I tried with trajectory and guides rails, it's the same problem...

Re: problem of maintaining a volume during a loft

SBix26 — Thu, 07 Jun 2018 13:20:43 GMT

The ability to attach .ipt files is temporarily (I hope!) unavailable. Zip the file and attach it.

Sam B
Inventor Pro 2019.0.1 | Windows 7 SP1
LinkedIn

Re: problem of maintaining a volume during a loft

Anonymous — Fri, 08 Jun 2018 07:35:43 GMT

this is (for real) the .ipt

Re: problem of maintaining a volume during a loft

TheCADWhisperer — Fri, 08 Jun 2018 10:12:09 GMT

Can you Attach zip rather than rar?

Re: problem of maintaining a volume during a loft

Anonymous — Fri, 08 Jun 2018 11:24:39 GMT

sure

Re: problem of maintaining a volume during a loft

TheCADWhisperer — Fri, 08 Jun 2018 12:46:23 GMT

I'll try one more time.

No third party software needed.

Only your Windows Operating System -

How to zip a file with Windows OS

Attach the resulting *.zip file here.

Re: problem of maintaining a volume during a loft

kelly.young — Fri, 08 Jun 2018 20:18:08 GMT

Hello @Anonymous I've reattached your file as .zip here for others to inspect.

It appears you are using 2012 so attaching my attempt won't help you much, but would recommend making sure your sketches are Fully Constrained and investigate using Sketch Blocks to define your shape so that you can easily use it in other sketches, just have to copy and paste.

In your case you would also have to mirror but using the block makes it much easier and controllable. That way you will only have to locate it in space with the 15° and 15mm dimensions.

Setting up a sketch in the middle could help drive the shape more accurately if you want to stick with Loft, but using Guide Rail Sweep would be best as stated prior.

Please select the Accept as Solution button if a post solves your issue or answers your question.

Re: problem of maintaining a volume during a loft

johnsonshiue — Fri, 08 Jun 2018 22:24:57 GMT

Hi! Many thanks for sharing the 2012 part! If I understood the design intent correctly, I do not believe you would get the desirable result by using Loft. The reason why Loft may not work for this case is about the section orientation and twisting. Loft does not offer any profile orientation or twisting control. As long as the loft face pass both sections and follow the rail reasonably, it is considered a solution.

I have a question regarding the 3D Sketch Trajectory. It looks like a 2D arc and positioned in 3D space. Shouldn't it be a helix instead? The reason why I am asking is that I still believe Guide Surface Sweep is what you need. However, the path is not reasonable. It creates awkward profile orientation no matter what Guide Surface I choose.

Many thanks!

Re: problem of maintaining a volume during a loft

Anonymous — Tue, 12 Jun 2018 07:11:07 GMT

Yeah, it's not an helix i need, it's this design exactly but without faultess in dimensions... therefore, I changed all my piece since this way was a dead end. Thanks for your help

Re: problem of maintaining a volume during a loft

Anonymous — Tue, 12 Jun 2018 07:17:50 GMT

thank you for those advices, I didn't knew all these details. Nevertheless, I tried to fully constrained my 2 sketches but no difference was there, so I did not pay attention to the .ipt I shared ... My bad ^^