The trim curves do not define a surface -- they only mark which part of the surface is to be considered trimmed away. If you have a trim curve that runs diagonally across a surface, the trim curve itself doesn't have any real relationship to the control points structure of the surface. In my opinion, one of the coolest modelling strategies in SOLIDWORKS is what I like to call the Skin and Trim technique! Now this may not be official.

• Surface Will Not Split Or Trim. Plz

In my opinion, one of the coolest modelling strategies in is what I like to call the Skin and Trim technique! Now this may not be official terminology but it’s easy to remember and trust me, you want to remember this one! The Skin and Trim technique is where we overbuild and intersect all of the surfaces that form the skin of our desired model volume and then trim them all back to meet each other with a clear view to achieving a solid model. There are 5 steps to the Skin and Trim technique which I’d like to introduce you to or refresh your memory on if you’ve tried this in the past and would like to give it a go again.

These terms may differ to what you are used to but this is the way I like to remember the steps involved, plus I wanted to keep the same letter throughout: Sketch! – Draw each of the profiles and/or boundaries that will represent each of your surfaces. – Choose the most appropriate surface features to build your surface bodies. – There are a few techniques which we can use to trim off excess surface geometry. – Moving from surface bodies to solid bodies couldn’t be easier with SOLIDWORKS.

– Get to work smoothing off your geometry for that silky surface finish. The subject of our blog today comes all the way from Christchurch, New Zealand! Which for me here in Scotland is waaay down under. Zach Medich is a passionate Engineering student and SOLIDWORKS EDU user who provided his awesome model of a 29er Mountain Bike for use in this blog post and I’m very grateful that he did as I’m sure you will be once you’ve checked it out. It just so happens that Zach is seasoned Skin and Trimmer much like myself which became apparent when he shared his model with me and I interrogated his ‘FeatureTree’. Many of his components make use of this technique and do so to flawlessly form solid parts that echo smoothness and shout out to TRY THIS TECHNIQUE! You’ll find a link at the bottom of this blog to Zach’s profile from which you can download his model and enjoy reviewing it as I did.

Let’s get to work then and focus in on the suspension pivot, part of the suspension system on Zach’s mountain bike, I’ve highlighted it in red in the assembly (Fig 1.0) and opened up into the part environment for a closer look (Fig 1.1 Sketch! We are going to start by drawing each of the profiles and/or boundaries that will represent each of the major surfaces that form the skin of this component. (Fig 2.0) represents the two sketch profiles used in an isometric view, the left open profile was created on the Front Plane and the Right closed profile was created on the Right plane.

Surface Will Not Split Or Trim. Plz

(Fig 2.1) shows these profiles when viewing normal to the Right plane and (Fig 2.3) shows them normal to the Front Plane. Next we want to choose the most appropriate surface features to build our surface bodies.

In this example the ‘Extruded Surface’ tool (Fig 3.0) will be used to extrude our sketches linearly into two separate surface bodies that intersect each other and represent the skin of our component. The open profile was extruded 150mm about the mid plane and the closed profile was extruded blindly 75mm (Fig 3.2). These two surfaces now completely overlap one and other which is not critical but helpful to the success and ease of this technique.

You can do this with as many surfaces as you want but you need a minimum of two intersecting surface bodies that are separate from each other. As you can see in (Fig 3.3) we actually have 3 ‘Surface Bodies’ because the open profile sketch contains two open profiles, so remember that you can actually create more than one surface body from a single sketch. As long as there are no self-intersecting sketch entities then this will work perfectly, thumbs up for multibody coolness!

There are a few techniques which we can use to trim off excess surface geometry, all of them reside in the ‘Trim Surface’ feature which we will be using here (Fig 4.0). Once you select this feature you will see the surface trim property manager (Fig 4.1) which contains two trim types, ‘Standard’ and ‘Mutual’ of which I’ll show both. The standard trim type requires me to select a trim tool that will be used to trim other surface bodies. You can use other surface bodies as a trim tool as well as a sketch, a plane, or a solid body. When using the standard trim you can only make one selection as the trim tool.

(Fig 4.2) highlights in blue the trim tool for this operation which as you can see I have selected in the trim tool selection box. I can then make the choice to keep or remove selections that intersect and are divided by the trim tool. When making these choices they are highlighted in orange by default as seen in (Fig 4.3) and added to the Keep/Remove selection box. This process can be repeated multiple times to achieve what you see in (Fig 4.4) The standard trim type is useful for fairly small trim operations but the mutual trim option, the second trim type available is incredible! Especially when you have many intersecting surface bodies and the graphics area is fairly cluttered (Fig 5.0). Ok, so let’s say you select the mutual trim type, first thing you’ll do is select the surfaces that you want to include (Fig 5.1) and they will be added to the surfaces selection box which now replaces the trim tool selection box as you can see in (Fig 5.2).

You’ll then want to choose whether to keep or remove your selections just as before with the standard trim type. The great power of the mutual trim type is that in SOLIDWORKS 2016 we now have 3 preview options to help us declutter our graphics area and make informed selections easily. When creating this model in SOLIDWORKS 2014 Zach would I’m sure have really liked and benefited from these new preview options. The ‘Show included surfaces’ option can be seen in (Fig 5.4) and you can see the selections to be removed highlight in orange as I hover my cursor over them. Selections already removed appear as wireframes and surfaces that are currently set to keep are shown in yellow, you could continue to make as many selections as you wanted. The ‘Show excluded surfaces’ option will highlight in yellow any surfaces that you have chosen to exclude through the trim operation.

Finally, the ‘Show included and excluded surfaces’ option which can be seen in (Fig 5.3) will show kept surfaces in yellow and removed surfaces will appear transparent. The ‘Surface split’ options at the bottom of the property manager can be simply summarised by saying that for this example – because our trim tool completely crosses the surface that we want to trim – they have no effect and are not relevant.

They only apply whenever a trim tool does not completely divide the surface you are trying to trim. For more info on these options check out this SOLIDWORKS web help link: Solidify! Regardless of what trim type was used, the core geometry that we were looking to achieve through the Skin and Trim technique is almost finished. It’s time to craft that Solid body we have been aiming for, know and love so much. Simple tasks like calculating the mass properties of a component or running an FEA analysis through simulation would be oh so simply impossible without a precious solid model. The solid body or solid model is the most complete type of geometric model used in CAD systems.

It contains all the wire frame and surface geometry necessary to fully describe the edges and faces of the model. In addition to the geometric information, it has the information called topology which relates the geometry together. An example of topology would be where the trimmed surfaces/faces meet each other at the curves/edges they were trimmed to. This intelligence makes operations such as filleting as easy as selecting an edge and specifying a radius value. There are a few ways in which we can take this model from Surface to Solid (Fig 6.0). Those with a keen eye among you would have noticed in the property manager of (Fig 5.2) that at the very bottom there is a ‘Create solid’ checkbox which becomes available when the surfaces selected in the mutual trim type form an enclosed volume.

In this case they do so that option would have been available once all of the selections were completed. That method of using the Trim tool to create a solid body could be added to (Fig 6.0) but I have left it out since we have seen it already. The three other methods are ‘Thicken’, ’Knit Surface’ and ‘Intersect’. We won’t look at those in this blog post but if you do want to check them out then see the SOLIDWORKS web help links below. Thicken Command Knit Surface Command Intersect Command Smooth! Now that we have a solid it is time to smooth off those sharp edges and enjoy the SOLIDWORKS RealView graphics experience of high gloss finishes and studio environments, well, among all of the other probably more important reasons for filleting.

A few Variable fillets later, some additional boss extrudes were added along with some further fillets, cuts and some more fillets. The whole process of creating this component was by my standards and I confidently suggest by SOLIDWORKS standards, very simple, easy to do and enjoyable. Try playing around with and incorporating the Skin and Trim modelling strategy to your component creation and see what results you can achieve!

Zach’s Mountain Bike model contains a variety of complex components which all start with this same technique and just look at what he was able to achieve with it! You should really see the whole bike! Nice one Zach. A special thanks to Zach Medich from Christchurch, New Zealand for his permission to use such an awesome SOLIDWORKS model for this blog post. I hope that you too can use this technique to produce models as good as his.

You can see more of Zach’s work and download this model on his profile by following the link below. Zach has certainly demonstrated excellent ability with SOLIDWORKS and I wish him well in his studies at the University of Canterbury. I myself worked as a Bicycle mechanic for 4 years whilst studying Product Design at Glasgow Caledonian University, so my appreciation for Zach’s interest in cycling and SOLIDWORKS is well informed by my own interests and experiences which are in common with his. Visit Zach’s profile by clicking on his bike below.