How do you untrim in Creo Parametric?

[pimm]

I noticed another similar topic where a user needed to untrim in Creo Direct Modeling. I tried some of the ideas but couldn't seem to make anything work.

Perhaps this works different in Creo Parametric.

I have tried Edit Definition to the imported IGES. I clicked the Edit Data icon and then clicked on an edge which I deleted. Unfortunately this doesn't untrim the surface in which the edge is attached to as shown in the video.

Any ideas how this would be done?

[TomD.inPDX]

Every piece of geometry is different. For the record, yes, that was Creo Parametric as well.

The other techniques discussed in that thread included rebuilding the surface using the edges to generate datum curves. Yet another technique was to add an independent feature from the 1st.

If you care to share the IGES file, we can see what we can do with it.

[pimm]

I'd really like to attach the part model but for propreitary reasons for the customer I wouldn't be able to do this.

I appreciate your help. I wish I could be better help.

I didn't understand how the independent feature untrim works.

I selected the already imported IGES and attempted to modify this imported model but couldn't seem to make this work.

This is quite frustrating as untrim really shouldn't be something that is this complicated.

[TomD.inPDX]

I understand about proprietary and fully respect this.

I also couldn't get the independent feature to work. Again, I think this is highly dependent on the status of the import feature.

Unfortunately, a surface definition can be defined many different ways for an exported file. Once a piece is removed, it is difficult to know what "was"there. Pro|E never really worked well with assumptions.

What I might recommend is creating boundary blends if the area to be filled is tangent or normal. You just need to add appropriate edges with datum curves to create the boundary. You might also look at sweep and/or blends.

If the data doctor cannot do it, you really only have the option of re-creating the feature.

[James62 · Accepted solution]

1.	Click Model ▶ Get Data ▶ Independent Geometry.

2.

Click Geometry ▶ Surface ▶ From Surface in Scan Tools.

3.

Select a surface to copy into the independent geometry feature.

This surface will then become untrimmed, and independent on the model.

That's from Creo help btw.

How's the surface going to be untrimmed is only dependent on it's U and V directions.

[Constantin]

"How's the surface going to be untrimmed is only dependent on it's U and V directions."

Let me add to that by saying that not all surfaces can indeed be untrimmed, because they might already show their domain.
If you read in an iges file and take a look at the text displayed (that normally you would just click away...) you will see that there are the types 142 and 144 referring to trim boundaries and trimmed surfaces. In most cases you will get trimmed surfaces. Even if you create a simple cylinder and export it to iges the circular faces are trimmed surfaces....

[pimm]

I appreciate all replies to my question. I see that I didn't follow the exact procedure to get the correct results.

I do like the route with Independent Geometry as I am trying to break the dependence of the original imported object.

It is helpful to see the IGES lines as interpreted as trimmed or untrimmed.

The method Jose suggested didn't work for me as I didn't break out the geometry initially.

I really have to say though that the whole untrim process could be improved.

1) The whole process of untrimming is very unintuitive. It sure would be nice to just have an Icon in the Editing area that allowed untrimming faces.

2) Creo doesn't do a great job of picking up the original geometry lines with the untrim. In some cases (such as converging corners) the untrim, followed by extend can be quite pathetic. I have an example which I'll submit for an enhancement request that shows that the software we are phasing out does a much better job than Creo with untrimming.

[Jose_Costa]

If you use the edit definition on the imported Iges (inside the called Import Data Doctor) you have to detach the surface first, then deleting an edge you will get the untrimmed surface. You can then use the "extend" or the "extrapolate" commands to redefine the boundaries.

The Independent Geometry is another good option like Jakub refered.

Another option is: "Model" tab -> "Surfaces" group -> "Surface Free Form"-> select the surface you want to untrim and press "enter" key until the end.