2 discrete parts, 1 nested. Modify only one without effecting the other?

[letsgoflori]

I have an object with 2 discrete parts/sections, 1 nested in the other.

I want to retain/lock the exact geometry of the first item, and augment/"sculpt" the second item to the first items geometry without modifying Any geometry of the first item.

Is the request stated clearly?

Does this perhaps have a “Name” or Feature type to search on the subject? 

Is Meshmixer capable of this task? Maybe other applications capable of a task like this, or a methodology that would allow me to accomplish this?

To clarify I have the geometry I want to strictly retain on the first item, and need to use the geometry of the first item to generate the finishing interfacing geometry of the second item.

The first item is critical that it retain a very specific geometry between the interface of the two objects, the second item is much more fluid in its shape, but does not mate to the first object “smoothly”, so I wish to sculpt the second object to a static geometry of the first item.

Is this possible?

Can I explain expand or clarify anything to get help?

If it is possible, would anyone have a tutorial to follow?

Thank You in advance! 

[laughingcreek]

a pic and the model would be helpful in answering your question.  

[letsgoflori]

Hi, thank you, anything else I can clarify or is perhaps poorly worded that I could rephrase?

To try and elaborate and explain, I am trying to build a 3D printed cast for a DIY snowboard boot sole. The negative cavity will sandwich and hold the Bale as the Sole is cast with a foam resin.

There are 2 parts to the object, a metal “Bale”, and a Sole.

I have 3D scanned a Sole, as well as have/am designing a few different Bales that are added to the scanned sole in Fusion 360.

The issue comes when I want to combine these 2 parts into a single cohesive unit, I want to blend the geometry from the free form scan of the Sole, to the geometry or the Bale which must retain its Exact geometry everywhere.

The existing scan of the Sole has geometry which is superfluous that needs to be removed but was needed for proper alignment of the modeled Bale, as well as the scan is “poor” in terms or exact geometry (but is fine for the intended purpose I think). So I need to take what was captured in the scan of the Sole and blend it back to the modeled Bale geometry.

The Bales geometry is critical to remain unchanged while blending the Sole to it.

I would like to sculpt the Sole to the Bale without the Bales geometry ever being modified.(Is there a name or type of modeling associated with a process like that? )

Hypothetically what I would like is if I sculpt the Sole it should reveal “covered” geometry of the Bale if Sole material is subtracted, and effectively only add material to the Bale geometry when material is added to the Sole.

The issue I think is (and I could Easily be missing something simple), I need the Bale to interpret the end geometry to add and blend the Sole to the Bale. Yet if I sculpt the Sole with the Bale it can/will modify its geometry.

I also need to somehow retain exact 3D placement between the two parts. 

Can I further explain any details or clarify anything else?  

[letsgoflori]

Using a equivalency as an example, as I find it difficult to even explain or find the words to ask. 

I would like to model a shape as if in real life, like if a person were to have a metal frame or skeleton and added and subtracted clay to it. The clay would be able to add and subtract around the metal framework, but at no time would the metal framework deviate from its dimensional geometry despite subtraction or addition of the modeled clay around the frame. 

The user could easily smear and blend the clay against the frame, but the frame would always remain rigid and dimensionally static. 

Does this modeling concept have a name?

Or can I accomplish it with existing or external tools?

[hfcandrew]

Do you plan on 3D printing your final model for a protypes? What's your end goal. That will dictate how the final mesh needs to be.

Either way will probably be something involving these steps:

Edit>Combine>Make solid 

Or

Boolean Union>Make solid

Or

Position your model how you want > Make a duplicate > Edit > Combine > use the sculpt tools

Can you attach the .stl's?

[letsgoflori]

>Do you plan on 3D printing your final model for a protypes? What's your end goal. That will dictate how the final mesh needs to be.

Any advice with that detail, how to approach the problem is Very helpful, just stumbling though the process for the first time.

My end goal is to marry these two objects, blend them together where the Soles geometry feathers into the Bale model logically.

This is strictly a personal project, I may make a handful of items for personal use.

Once I have a reasonable composite model, I plan to construct a negative composite model by 3D printing that will sandwich the metal Bale inside the negative mold of the composite object for casting. Further details required?

Yes I can include any files requested. Individual files for the constituent parts are what is being requested?

Seem to be having difficulty attaching the .stl files with this sites "Attachments" tool, Is there perhaps a better way to post files here? It sees to keep failing to post anything I try to include. file size  284kb and 3.7MB .stl files

[hfcandrew]

Okay that helps a bit.

And ya, frustratingly, this forum focusing on .stl design does not allow for posting .stl. Haha,

You can try: A) In MM export the file as either binary, or ASCII, sometimes that works

B) Upload to a file share such as Thingiverse, or Google Drive etc then give a URL

C) Zip the .stl file

[letsgoflori]

I can export in another file type also if it is helpful? STL was simply requested.

Trying both files zipped into a single archive:

[letsgoflori]

May I also ask bluntly...

Is this the correct tool for the job? If you or anyone else knows or has a alternate sugestion or advice?

I just know meshmixer is a fantastic free option for 3D sculpting, and there is a huge amount of support for it based on individuals in the 3D printing community.

And does this type of specific modeling perhaps have any useful Terminology associated with it for searching? That is one of the most difficult things is to simply find words and terminology associated with the concept I am trying to convey, and what I think I need to do.

Which TBH I am not exactly 100% sure I am even approaching the problem correctly...Its very possible there is a much better way to work the problem of adding an isometric cad model to a scanned model, and be able to manipulate the interface between them in the way I think I need to.

Thank you for any help or advice!

[Anonymous]

Hmm, sorry I still do not understand your problem.

As long as you have two separate objects you can modify each without touching the other.

A basic idea in mesh modelling is to modify each object first and to join them to a single one (either by Boolean operations, Combine or MakeSolid) as a very last step.

Here's a screencast of what I think you intend to do. The basic workflow:

- Use EDIT/GenerateFaceGroups on the sole to get meaningful groups for the Bale region in the scan.

- SELECT these groups and manually refine that selection.

- Separate this selection and set the resulting object as a Target (magnet icon in the browser)

- Use Transform to move your new Bale to a position near to the target

- Now select your new Bale's regions which should fit to the old surfaces in the target

- Run Edit/AlignToTarget on that selection

- You may correct the resulting position manually now.

- Disable the old bale target and delete it.

- On the remaining sole use the smooth brush to smooth the open boundaries.

- Run Inspector to close the holes

- Modify the shape of the sole as desired (using SCULPT or an other tool in MM)

- Finally join both objects (here I used Boolean difference to get an object to be printed in a soft material and made a duplicate of the bale to keep the stiff element)

>> You now might run EDIT/Combine to join both shells in a single object to send it to a dual material printer

Screencast will be displayed here after you click Post.

90abcace-9713-4fd2-96ac-a2232860fa23

If you really want to join both objects and to modify the sole only (not recommended):

You can activate both objects and run EDIT/Combine.

Now the combined object owns two face groups.

You can restrict SCULPT tools to affect the group under the cursor only by activating the RestrictToGroup checkbox in Filters.

Another option is to keep both objects separated and to set the bale (in its right position) as a Target (in the View menu you might want to disable TransparentTarget).

Now you might enable BrushOnTarget and/or set some AttractToTarget weight (both options in SCULPT > Filters).

This way you can use some skeleton structure to apply clay on it expanding an existing object. You can't apply clay were's no such material so you may need to insert some MESHMIX primitives to act as cores to sculpt on....

[hfcandrew]

@Anonymous as usual the screen cast did not get embedded. I usually just post the screencast URL because of this.

@letsgoflori MM can do it, and really do anything any other program can. The problem here (and with most other posts) is just trying to figure out what your precise 'it' is.

[Anonymous · Accepted solution]

Ok, second try to insert the screencast (think I broke it editing the post to correct a typo)_

[letsgoflori]

Thank you for taking the time to do that, beyond anything I hoped for or expected! I searched and looked for any technique comparable that I could equate it to, and could not find anything relevant to follow.

That is a complete step by step detailed map of the actions I needed to take and can repeat, I am as certain that should get me were I need/want to be fundamentally!

Thank You Very Much! u/MagWeb !