Plasticity 3D – CAD for Artists

Plasticity has caused quite a furore on the internet and in some forums of the maker scene in a short space of time. There are already hundreds of tutorials on YouTube, mostly by enthusiastic users who proudly share their first experiences and knowledge of the fairly new programme. Many of these videos have already been viewed by thousands of users within a short space of time and have received plenty of comments. We took a quick look at the latest version – and were equally impressed.

Design history and parametric modelling – or just simple direct modelling?

The release of Pro/ENGINEER in 1987, which introduced chronology-based parametric modelling to the CAD industry, is generally regarded as an important milestone in the history of computer-aided design (CAD). Since then, this modelling principle has been used in the most common CAD programs. The advantages of this method are the ability to retrace every design step and to edit all parameters, such as dimensions and dependencies, retrospectively. However, this work requires correct planning and structuring of the projects and some effort, e.g. when creating the obligatory sketches with dimensions and restrictions… Anyone who tries to model something “on the fly” with CAD software without prior knowledge is likely to be frustrated at first.

Plasticity as a pure direct modeller promises a remedy here. Reminiscent of the UI and workflow of Blender, modelling should be quick and easy – even for artists who are not so familiar with CAD – and shy away from the effort required to see results. Plasticity does without some of the important functions for the CAD industry: no parametric editing, no design history, no editable sketches with dimensions..

Is this a new Blender – in slimline?

Plasticity starts with a tidy interface. In the centre is a 3D work window, just like in Blender – even with the obligatory cube. There are no menus to be seen, just a few icons arranged in groups, which seem somewhat self-explanatory. Tool tips help to recognise the functions that are easy to understand at first glance. At the top left is a small circle with a “P” on it and a tick next to it. A menu can be opened here, including file commands and access to the preferences. Below this is the equivalent of Blender’s Outliner (lists all objects in the project).

At the bottom left there are icons for transformation and quickly accessible commands (Boolean, Cut solid width curve, Mirror, Duplicate Object). On the right-hand side of the work window, a vertical icon bar shows the actual tools for creating various curve shapes (Line, Spline Curve, Centre circle…) and for editing them (trimming, adding new points or generating a bridge curve between two reference points). You can also create “solid” bodies (sphere, cube, cylinder). Context-sensitive input windows and icons for additional functions are provided for all tools. Help for shortcuts to various options is also displayed. The “f” key can be used to call up a list of all program commands, assign shortcuts or define favourites for the search menu. At the top right are navigation elements and a switch to change the render mode. At the top left, similar to Blender, there are icons for changing the editing modes: points, edges, surfaces, objects – already assigned the numbers 1, 2, 3, 4 by default.

On the right, outside the work window, snap functions and construction planes can be switched, on which, for example, new objects are aligned in space when they are created (XY, YZ, XZ, Plane from Camera, Plane from Selection – with the Space button, the current selection also becomes a “Temporary construction plane”, which can be called up again until a new selection is made. The alignment of the construction planes represents Plasticity’s grid. In addition, some information about the current performance in FPS and about selected scene objects is displayed.

Even if at first glance you might have the feeling that you are looking at a slimmed-down version of Blender’s Polygon Modeller, nothing is polygonal – everything is NURBS with the corresponding special features. In some cases, the software seems to be able to deal better with operations in which polygon objects for smooth surfaces must consist of very dense meshes with many polygons, while the shapes in Plasticity are first “calculated” independently of resolution with the help of NURBS (Non-Uniform Rational B-Splines). Polygon meshes are only created during export, e.g. for 3D printing (.STL or .OBJ) or for further processing in other 3D applications. Plasticity offers various options for exporting with preview views of the respective mesh.

First steps – cubes

For the first steps in Plasticity, we accepted the obligatory cube and simply “played” with the functions offered. What was striking was the sometimes really quick and easy access to various functions, which hardly differ from Blender’s polygon workflow. The selection of points, edges, surfaces and objects is reminiscent of Blender. Even Blender’s shortcuts and navigation commands can be found again (navigation presets for a whole range of 3D tools can be selected in the preferences (Blender, Maya, MoI3D, 3ds Max, Fusion 360, Rhino). The object manipulation tools, such as transformations, array functions (linear, radial) or Booleans are fairly self-explanatory and quick to use, as they can be called up with a single click. In contrast to Blender, where a huge range of functions is also achieved through add-ons and non-destructive modifiers, Plasticity tries to score points with simplicity and quick function calls. We found it a bit of a pity that although the dimensions of objects, for example, can be entered easily and accurately when creating them (Plasticity can even do the maths here!), the other ease of use seems to be missing when editing later.

For example, to subsequently edit length, width, angle or position, Plasticity only offers to change the existing shape relatively (e.g. scaling factors). Plasticity does offer several options for subsequently defining dimensions in absolute terms, but probably no longer with just one click. Commands such as moving, scaling or rotating “matching” objects, which offer definable snap points, use the “Freestyle” option, for example. In this mode, objects can be precisely positioned and aligned with each other, among other things. The absolute size can also be defined in this way. When scaling, a starting point must first be defined (e.g. the centre of an object surface) in order to then define absolute values for the transformation of an opposite surface from there. Snapping to reference objects also works. Object lengths can also be determined by displaying the length of edges or faces. Users who are spoilt for choice would be pleased to be able to enter or edit such parameters later – especially as Plasticity displays various data for selected objects anyway: in addition to the position, the length of curves, the curve length (the circumference) and radius for circles and the surface area and volume for solid bodies – even in different units of measurement.

In addition to the transformations of solids (still our cube), all edges and faces can be edited as required. If one or more edges, even of different objects, are selected, the Fillet tool is automatically available. Depending on the direction of movement of the mouse pointer, either a bevel or a soft chamfer is created. Bevels can be subsequently deleted or further edited in the same way as faces – the values from bevels on other objects can also be adopted with a click of the mouse. When faces are selected, the extrusion tool is automatically activated.

Sharp curves – 6 tools for everything

With a total of 6 drawing tools, all necessary curved shapes can be created: Line, Spline, Circle, Regular Polygon, Spiral and Rectangle. There are options for some tools, e.g. Spline Curve or Control Point Curve – can be changed during drawing using the Tab key. Other options relate to whether shapes, e.g. circles, are defined from the centre or via control points. The sharp corners of lines can be smoothed with the Fillet function (b) (or with the Convert vertex command). Curves can be joined together (if the end points are in the same position). Spline curves can also be deformed, as in other programmes. It is not necessary to activate the Move mode for this, as is usual with Blender. It is sufficient to click and drag vertices or control points directly with the cursor in point mode. By additionally holding down the Alt key, a curve can be proportionally deformed up to the next control vertice. Extend Curve achieves interesting results. This allows you to “continue drawing” open curves that have been started according to various rules – or to shorten them. This creates further harmonious curves.

Essentially, Plasticity offers 4 methods to generate bodies from curves:

• Pipe (P) – a simple way to extrude profiles on a curve. The default setting is a circle. In earlier versions, it was probably still possible to use profile curves. This was not available in the current version. Pipe can be a cool way to add details to objects, e.g. if the edges of bodies (or painted curves) are used as pipe curves to cut profiles into the surfaces (Boolean Difference) or to apply ornaments (Boolean Union).
• Sweep (Shift P) – like the Pipe tool, to extrude profiles along curves. There still seems to be potential here – some other graphic tools offer taper options or scaling of cross-sections at junctions or twists..
  Revolve – contours are rotated along an arbitrary axis – without flourishes.
• Extrude (E) – corresponds to what is known as the extrusion of curves or surfaces. It is possible to specify a thickness during extrusion
  during extrusion. Angles can be specified for the extrusion of surfaces. For example, a pyramid can be extruded from a square instead of a cube.
• Loft (L) – perhaps the most interesting option in Plasticity, because curves can be combined quite easily to create beautiful smooth surfaces and Plasticity is quite convenient when designing 3D curves. As mentioned, curves can be drawn in various ways, but can also be obtained from the surfaces of 3D objects. The easiest way is to duplicate existing edges, e.g. on fillets or the intersections of Boolean functions. However, it is also possible to draw directly on the surfaces of objects or to project curves onto them.

In this way, for example, you can obtain three-dimensionally curved curves that are adapted to the surface of the bodies. This makes it relatively easy to provide more complex three-dimensionally aligned curves for the loft objects.
The shape of loft objects can also be controlled using special guides (control curves). Plasticity offers different continuity settings for loft and patch objects (“plugged” holes in surfaces) in order to achieve smoother transitions on surfaces. It was not always possible to achieve optimum results immediately in the test if the geometric specifications were probably too “critical” for a satisfactory calculation by Plasticity.

Conclusion

We don’t want to get involved in the discussion as to whether Plasticity 3D represents a revolution in 3D modelling or is not a CAD program to be taken seriously. Plasticity does not come close to the functional scope of large – and in some cases expensive – CAD applications. It also lacks typical, quasi “standard features” of CAD programs, such as chronology-based parametric modelling or customisable dimensions and special editing functions. Plasticity 3D is unlikely to compete with established CAD applications for industrial design.

However, users can start using direct modelling almost immediately and quickly achieve results, even without extensive prior knowledge of complex CAD programs and without preparatory measures (including time-consuming sketching with correct restrictions…). Although or because the UI is reminiscent of Blender’s modelling workflow – Blender users will quickly find their way around – we found the introduction to NURBS-based modelling in Plasticity quite accessible. Many modelling tasks go surprisingly quickly after some practice.

We particularly liked the easy-to-use curve tools and the ability to create harmoniously curved surfaces from 3D curves. Easy-to-use curve tools, extrusion and rotation solids, sweep and Boolean functions, cutting solids with curves or “hollow a solid” with just a few clicks – and of course the cool fillet functions make you want to model with this software. There is already another beta version, which will include a bridge to Blender to make it easier to combine the advantages of both programmes. Given the pace of development of the software to date, this could be expected soon. Then even more users could possibly follow the advice from a forum and try using both programmes in a complementary way. After all, it costs nothing to test the free demo version. We look forward to further developments.

Indie: 99 dollars (plus VAT) Use on 2 machines simultaneously, version 1.x updates included
Studio: 299 dollars Use on 4 machines simultaneously, all updates included for 12 months, including major versions (2.x) Access to the beta programme for 12 months

Mandatory for companies with more than 10 employees
30-day trial version: free Windows, MacOS (M1), MacOS (Intel), Linux (deb)