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LeChuck

Help with vacuum formed plastic modelling

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Hi,

 

I’m fairly new to C4D and I’m having a slight issue with how to approach modelling a vacuum formed plastic lid for baby food packaging.

 

I have attached two reference photographs of what I’m trying to achieve and my C4D model of where I’ve got to. 

 

I am pretty happy with the overall shape/topology of the lid. For the security icon I have just projected a spline onto the dome geometry and extruded with rounded edges which works well for me.

 

The issue I’m having is trying to get clean geometry for the vacuum formed spoon shape on the dome of the lid. I have tried multiple methods to get this as a clean piece of geometry but am running out of ideas. I have also tried Boole as a starting point and then to clean up the mesh but it gets messy quite quickly.

 

Ideally I want to have that whole lid (inverted dome, dome and spoon shape) as one object which I can drop into subdivision surface. At the moment the spoon shape is its own object which is just positioned to intersect with the dome.

 

Any help would be greatly appreciated, perhaps I am approaching this in the wrong way or there is some method for this type of modelling which I’m not aware of? Either way any tips or guidance in the right direction will be much appreciated!

 

Thanks 

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Baby_Food_Lid_Model.c4d

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Posted (edited)

I've had a look at your topology. You may be pleased with it, but I have to say, perhaps incorrectly so - I'm afraid it's not ideal anywhere on the model, and although some bits are pretty close to being OK, other bits of it specifically break modelling rules, and contain multiple elements that will compromise the SDS you are using throughout...

 

The 'collar' section looks kinda passable under SDS, but the topo there, whilst not awful, isn't great either, and not quite high enough res to describe the form nicely. The angled lid is not too bad either, except for the bits that really should be connected to it and not separate. But the blobby details really need some love, and the places where curved sections meet smaller angular details is not A-grade anywhere.

 

Now, I say all this, but actually most of the mistakes you have made are understandable, and those that everyone makes when new to modelling or tackling an object that is slightly outside of their current skill-set. You are simply lacking the years of experience required to know how to construct this well. The trouble is of course, is that there is no way for me to transfer that to you in any single forum post ! I would need a 3-4 hour live skype session with you to go over how to model this properly in anything like the level of detail required. So the best I can do here is to give you some general guidance on how to tackle this.

 

The hand is the only thing you can model separately here (unless you are using the volume builder) - the other lumpy bits are clearly part of the lid with visible and much more gentle transitions into it, so those cannot be separate parts. The hand itself you should model flat, out of polygons, mesh project onto the lid object, and then add thickness to it once it is in place.

 

  • The lid / collar itself should be using symmetry initially so you half your workload. 
  • The edge flow on the lid should be mainly circular / oval-form throughout the model.
  • You need to define your initial polygon density based on the smaller details in the mesh NOT the minimum amount of polys required to describe the form.
  • Polygons should ALL be quads, and not only that, they should be evenly distributed, not degenerated or convex, flow around the model rather than across it, and should be even and regular in construction, with matching edge counts for neighbouring parts.
  • You also need a lot more of them than you are currently using, which is how you will get this 'neat' eventually.
  • You should begin with disc primitives with FFD deformers (that you will almost immediately apply and not leave 'live') to achieve the perfect cylindrical border density / distribution.
  • The hand should not be built from a spline where you don't have control over topology to make it curve correctly on the lid.
  • Thinking ahead is one of the most valuable skills you can deploy with this mesh. Try and be acutely aware of how every move you make affects a future process, or a related part of the model somewhere else on it.
  • Start by outlining the principal forms with primitives and / or the poly pen.. define inside and outside borders where appropriate, and carefully choose initial segment counts that are mathematically compatible with other segment counts you have used in other parts. 
  • Try and identify ways to use existing topology to gain secondary advantages with things you need to add next.
  • But also realise which polys should remain exactly where they are because they are primary edge flow definers.
  • Establish / nail down your curvature early on.

 

Those are my initial tips, but I am very busy with client work today, so will keep popping back throughout the day to add to them as and when I have time...

 

Don't lose hope though - a model is almost always better the second time you try, and early failures are nothing more than waypoints on the path to your eventual success and valuable XP for your future modelling endeavours !

 

CBR

Edited by Cerbera
Added info pls refresh page

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Hi Cerbera,

 

Wow thanks for all your detailed advice! I'll be sure to research the topics you have mentioned, especially edge flow as I often find myself stuck when modelling with no choices left but to resolve mesh issues by adding triangles. I read that having a good edge flow on a model will prevent you from having to do this so perhaps I will practice this technique on a simpler model just so I get the hang of it.

 

Also interesting about the disc primitives and FFD deformer which is a new way to approach this that I hadn't thought of. 

 

And totally agree with you on doing a model second time round. I find myself remodelling things over and over as I sort of feel the model isn't quite right and am always surprised at how much better the results are each time just by approaching it with a different method.

 

Thanks again for your tips on this!
 

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Hey,

 

I've had a go at a second attempt and feel I have definitely improved the quality of the model i.e. there is now no pinching at all in the rendering. There are a few instances of triangles in the base mesh (in the corners of the semi-circle holes on the latch, and in the raised curved corners) as including triangles actually looked better when subdivided. 

For all the details like the arrow and the grip lines etc I have used displacement in Octane which gave me a pretty good result. 

I had to give up on the spoon in the end as no matter what I did I couldn't get it to work properly. I tired your FFD suggestion as well as other methods such as trying to use a displacement and also trying to use sculpting. Neither gave me the results I wanted so I will have to admit defeat for the time being – as you say I am probably not experienced enough yet to model something of this complexity. Perhaps I will revisit this project at a later date.

 

Thanks again for all your help!

 

 

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Plastic_Lid_2nd_Attempt.c4d

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