Sculpt using a non-planar surface as an origin

[Anonymous]

I'm working on components that don't have planar surfaces. The  component body is made by splitting a solid body with surface patches created by lofting between two different spline profiles.

On the surface of these components, I want to be able to 'scoop out' irregular shapes (e.g. shapes I created in the Sculpt environment).

On faces that are almost flat, I can do this by creating a 'tool' shape in the Sculpt environment and use this tool shape to split the body of my target component (and remove the surplus). This doesn't work very well at all on surfaces that have a more curved profile.

Can anyone tell me a good way to do this please? I've attached a few screen shots from Fusion 360 showing

1) The component I am trying to modify

2) The same component after I used the above tool to scoop out a small chunk. This shows the complex shape I am trying to scoop out of the curved surface - not something I can create parametrically or by extruding a sketch. Note that this only worked as the surface of the component is almost flat at this point

3) The surface patch that I used to create the profile of the component - the patch is a loft between splines of different shapes. The component is present is this shot for orientation.

Does anyone know of a good way to do this? I've been trying (and failing) to create faces on the curved surface in the Sculpt environment - but there may be a better way.

Thanks in advance.

[mavigogun]

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@Anonymous wrote:

On faces that are almost flat, I can do this by creating a 'tool' shape in the Sculpt environment and use this tool shape to split the body of my target component (and remove the surplus). This doesn't work very well at all on surfaces that have a more curved profile.

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Why/in what way does this method 'not work very well'?   Does Fusion fail to calculate the form?   It would help to see the Sculpt form you'd like to extract juxtaposed over the target.

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@Anonymous wrote:

Does anyone know of a good way to do this? I've been trying (and failing) to create faces on the curved surface in the Sculpt environment - but there may be a better way.

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Some workflows occur to me- but you might find them inadequately inflexible.   I might start by defining the region on the target surface with a split; the resulting edge may be Projected to a Sketch or Lofted to be used as a former in the Sculpt workspace, conforming the Sculpt body to it's edge with tools such as Match and Pull.

[Anonymous]

Hi,

Thanks for the reply. You asked why I said using a cutting tool didn't work well. Fusion doesn't have any problems with the tool - it is calculated without error. It's just that I can't figure out a way create the tool so that it follows the contours of the surface I'm trying to use it on. 

I've attached a photo of the tool that I created (viewed from below). If you look at the periphery of this tool, you'll see that the outer edge is flat. This is because I created this tool as a series of faces on a planar surface. I then manipulated the central edges/faces/vertexes to the shape that I wanted - but I couldn't figure out a what to make the periphery of the cutting tool conform to the shape of the body that I was trying to cut it from. This means that when I sink the tool into the main component body, the periphery of the tool cuts quite deeply at the centre (where the cross section of the target component is at its highest) but hardly cuts in at all where the profile falls away at the edges.

Note that this peripheral edge is required to make a small indentation/cut all the way around the 'scoop' that I'm working on. 

The problem is most evident when you look at the attached section analysis. You can see that the tool makes relatively shallow cuts into the target body at the left and right edges - whilst it cuts quite deeply in the centre. This is why I want to be able to create a sculpted surface (faces in the sculpt environment) that follows the contour of the target body (in both X and Y) prior to the relevant parts of that sculpted surface being pulled/manipulated the centre of the tool to the required sculpted shape.

So, my chief problem is that I can't figure out a way of creating a sculpted body/surface that conforms to the profile of my target body before I start to manipulate it.

I can create this peripheral edge by other means and make it conform to the surface of the target body (e.g. by using the method described in the latter half of this video - https://www.youtube.com/watch?v=wfVsQlh2ELM). However, this still doesn't help me to create a 'sculptable' tool body that conforms to the surface of the target body.

I'm pretty new to Fusion (you can probably tell) so I'm not yet familiar with the Match and Pull tools you mentioned - I'll have a look now.

Thanks again for your input. I'm hoping this reply clarifies what it is that I'm struggling with. If you can think of a better way of getting a sculpt body to start off as the same profile as the target body then I'd be most grateful to hear about it.

Best regards

Simon

[TrippyLighting]

A T-Spline surface is never going to be able to exactly follow a curved surface created with the modeling methods in the Model environment. The math just does not work out that way. It is able to approximate it with some tolerance but it is not going to be perfect.

I am not quite sure why you feel that the sculpted surface needs to exactly follow the surface of the other object.

You might want to investigate the tools in the patch workspace.

Can you share your model ?

[Anonymous]

Thanks for the feedback - I very much appreciate it.

I've shared an example as requested (link at the end of this message). Here is how I did it: -

• Created a rectangular body and extruded it.
• Created a spline at each end of the rectangular body and used the Patch environment to create a loft between the two splines.
• Cut the main body using this surface patch and removed the excess. This leaves me with the non-planar surface that I want to cut (scoop out) a sculpted profile from.
• Created an offset plane. This plane will be used in the sculpt environment to create the faces that I’d like to sculpt. I didn’t have to do this step – but it keeps the sculpt away from the main body so it is easy to see what I’m doing.
• Drew a sketch on this offset plane with the outline of the shape that I want to 'scoop out'.
• Went in to the sculpt environment and created faces using the above sketch as a guide. I manually moved the vertexes around until I got the shape I wanted. At this stage, my problem (and my question) become evident. The outer vertexes and outer edges of this sculpted shape are all flat (as I had to create the faces on a planar surface). I want to create these outer vertexes and outer edges so they conform with the shape of the surface of the main body that I want to scoop out from.

Of course, this is where I could be trying to do something completely invalid. Perhaps there is a better way of scooping out the shape in this example from the curved surface/profile of the main body.

My questions are: -

1. Is my approach completely wrong? Is there another way to ‘scoop out’ the sculpted shape I have detailed from the curved surface?
2. If not, how do I get the outer edges/outer vertexes of my sculpted shape to conform to the curved surface of my main body before I start to move the inner edges/faces/vertexes to the shape I want (and then scoop this shape from the surface of the main body)?

Here is a link to the shared model - https://a360.co/2LNPTdJ

[TrippyLighting · Accepted solution]

Let me first say that you can remove the sculpted area from the solid but is is likely no the right technique.

This would net work with the sculpt you have designed because it does not comprise a closed surface as it has gaps.

You should also not use any triangles in a sculpted shape.

Is this what you are looking for ?

Here's a smoother version of this:

[Anonymous]

That's exactly what I'm looking for - thanks.

How did you do it?

[davebYYPCU]

I think you are trying too hard, after sculpting, come back to Patch and modelling areas as needed.

make the cutter a solid, by patching the top surface, (Sketch on Offset plane)

insert the cutter to the required position in the body to cut.

Modify > Combine > Cut the cutter out of the target material

or use the cutter as it is now and then use boundary fill to create the body of the void, again cut it with Combine Tool.

Oops, Trippy posted while I was typing, he has done what I said, while I have not opened your model, to find the other things he mentioned.

Might help....

[Anonymous]

Thanks again.

I thought I'd tried that - but I guess I am missing something. Would you be able to share the changes you made so I can follow along and see what I'm missing?

[Anonymous]

Just realised I was replying to another poster - oops 🐵

The form that Peter Doering has created is exactly what I'm looking for. I'd be most grateful to see/hear how he achieved that

[TrippyLighting]

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@davebYYPCU wrote:

... he has done what I said ...

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I would not use sculpted geometry in this case but go right to the Patch environment.

[TrippyLighting · Accepted solution]

Here is a screencast/YouTube video:

[Anonymous]

That's absolutely fantastic.

Thank you so much for your help. I would never have thought of doing it like that (looks like I was doing it wrong all along).

I only started using Fusion a few weeks ago and have never used a CAD package before. Everything I have learned is from watching videos such as this.

Thanks once again - you're a star 🐵

Cheers

Simon

[TrippyLighting]

Yu're welcome! You might click the "AcceptSolution" button 😉

I believe that would make #1000 of solutions provided.

[mavigogun]

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@TrippyLighting wrote:

I believe that would make #1000 of solutions provided.

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Still, no level 12- you'll have to settle for the esteem of your peers.