topic Surface gaps in Inventor Forum

Surface gaps

luke_zagurski — Wed, 02 Aug 2017 14:28:43 GMT

Is there any way to fill these 2 small gaps.

The boundary patch was based on an existing part not created in inventor. For some reason it did not like the corner area.

Thanks

Re: Surface gaps

Thomas_Savage — Wed, 02 Aug 2017 15:43:16 GMT

Hello,

Could you attach the .IPT please?

Thanks,

Thomas.

Re: Surface gaps

luke_zagurski — Wed, 02 Aug 2017 16:36:27 GMT

Here it is.

Re: Surface gaps

JDMather — Wed, 02 Aug 2017 18:56:37 GMT

Not sure about your design intent - but is something like the attached what you are after?

Re: Surface gaps

luke_zagurski — Wed, 02 Aug 2017 19:18:12 GMT

Yes that is eventually the idea, but I'm trying to create a lens to the front.

I have attached another one and you can see that I sort of got it, but if you go zoom in on the corners of it it still has those little gaps that I can't seem to shake.

Re: Surface gaps

johnsonshiue — Fri, 04 Aug 2017 21:41:29 GMT

Hi Luke,

I vaguely remember seeing the exact model a while back. Maybe you posted it or somebody else did it. This is kind of a bug or a limitation in Boundary Patch. BP tries to fit a G2 continuous surface on a given loop. Depending on the continuity of the loop, sometimes a G2 surface may not be found. BP could loosen the loop tolerance in order to find the G2 surface, leading to a gap like this.

Instead of creating BP over the loop, I think it is better to restore the base surface. I am not sure if you are aware of a workflow like this.

1) Create a zero offset surface on the thin face.

2) Copy Object -> pick the offset surface -> send it to Repair Environment. The surface will be copied to RE.

3) Edit RE -> Extract Loop -> pick the inner loop of the surface -> check Delete Wires. You will get the untrimmed surface defining the thin surface.

I think this is the surface you need. BP will only complicate geometry in this particular case.

Many thanks!

Re: Surface gaps

luke_zagurski — Mon, 07 Aug 2017 17:39:28 GMT

I'm not seeing an "Extract Loop" command. Is this something that's only found in Inventor Professional? I'm using Inventor 2017.

Thanks

I see it now. I had to "copy to construction" first.

Re: Surface gaps

luke_zagurski — Mon, 07 Aug 2017 18:17:50 GMT

It worked as far as giving me a surface to the outer loop. If I wanted to use the inner loop to create a lens from how would offset (or make smaller) the one I created with your technique?

Re: Surface gaps

luke_zagurski — Mon, 07 Aug 2017 19:26:01 GMT

I tried Boundary Trim and thought I hade it, but it still gives me the two small strange gaps in the righthand corner.

Re: Surface gaps

johnsonshiue — Mon, 07 Aug 2017 23:18:36 GMT

Hi! In Copy Object dialog, change the Output to "Create New" -> Repaired Body. It will copy the surface to Repair Environment. Edit RE and you will see Extract Loop command (there is a similar command in Construction Environment too).

I am sorry it is not clear what you are asking in terms of smaller loop. Could you attach what you have?

Many thanks!

Re: Surface gaps

luke_zagurski — Tue, 08 Aug 2017 12:01:28 GMT

Iv'e attached what I was able to do with boundary trim, but it still gives small gaps towards the corners .

This is the surface that I would like to create my lens from. I will also need to make it .02" all around so it has some wiggle room.

Is this possible as a surface or is that easier to accomplish as a solid?

Re: Surface gaps

johnsonshiue — Tue, 08 Aug 2017 13:20:41 GMT

Hi Luke,

I see the issue now. The tiny gap is due to double-conversion. You extract the loop and the loop is converted to 3D sketch wires. Then you trim it again. Actually, there is a better workflow to avoid precision loss. Go back to Repair Environment. Instead of using Extract Loop command, use Edit Region command. Select the inner region, you will get the ideal trimmed surface. Please take a look and see if it works for you.

Many thanks!