Splinepatch
Introduction

SPLINEPATCH 2.5 is by the same developer as the awesome DRIVE plugin developer, Klaus Heyne at http://www.c4dplugin.com You can read the review of the DRIVE plugin here.

Even before I received the plugin to review I had a feeling that it was going to be another terrific plugin, as the DRIVE plugin from the same developer is quite exceptional. In this review in addition to just reviewing the plugin I´m going to try and explain it´s usage. It´s very similar to the DRIVE plugin in that there´s a lot of power but you do need to spend some time learning how to use it. In the case of SPLINEPATCH not only do you need to learn how to use the plugin you have to learn how to model with CINEMA 4D´s splines and this requires a different approach than regular polygon / box modelling techniques.

What is Patch Modelling?

If you haven´t heard of patch modelling before it´s nothing new. Other 3D applications like Lightwave, Maya, Animation Master and 3D Studio Max have it or something very similar. The idea is to create spline cages and patches (surfaces) are created between the splines. In C4D you create a patch with either 3 or 4 splines. Each patch is then welded together by making the patch objects child objects of a Multi Patch. Typically you create your splines over background reference images. The power with this modelling technique is that you can create very smooth curves with splines and usually bezier splines. The splines can be easily edited later. An analogy would be be creating curves / splines in a 2D vector drawing program where it´s a lot easier to create smooth curves than drawing them freehand.

Below is an example of what I mean. Here I´m modelling a VW Beetle. A very curvy car!! I´ve traced around the rear guard in several views and used SPLINEPATCH 2.5 to create the surfaces between the splines. I´m able to get very smooth curves using bezier splines.

VW Rear Guard

Side view. Splines drawn to match reference image.

VW Rear Guard Perspective

Perspective view. All splines selected.

You can see how few splines are required to create the guard. In this case there are 5 patches and these are welded together to make the transition between them smooth. There´s nothing that you can´t really do with regular polygon / box modelling but modelling with patches is another technique that in some cases like with the VW guard is a lot quicker. You can if you wish convert the patches into regular polygon objects and or drop them under hypernurbs objects. I´ll go into more detail shortly.

Here´s an hour or two later. I´ve changed the spline colour to blue to make the splines more visible. When you do spline modelling and only model half of the object it´s absolutely essential that you zero out the X and Y axes on the bezier handles, otherwise you´ll have noticeable seams on the symmetry line. This is best done from the structure manager.

Completed VW spline cage

Completed spline cage.

SPLINEPATCH Plugin

The plugin is downloaded from the developers site and is only 863kb in size zipped up. Like the DRIVE plugin you have to run the installer exe and this installs the plugin. For those weary of what the installer does. All it does is create a folder in your plugins folder and extracts the plugin there. When you fire up the plugin´s 3 tools / objects appear on in the plugins menu. You´ll most likely want to create a layout just for working with SPLINEPATCH as you´ll be using these tools and commands frequently plus tools and commands for working with splines. The plugin is also linked to your C4D serial number and the developer will supply you with a SPLINEPATCH serial number that you need to enter when you first run C4D after installing the plugin. The plugin is available in English, German and Japanese versions.



Splinepatch tool and objects

The SPLINEPATCH plugin menu. One tool and 2 objects.

You´ll also want to download the manual which is 1.3mb in size. Like the DRIVE plugin manual the SPLINEPATCH manual is very detailed. To understand how the plugin works you´ll need to keep chipping away at the manual and testing things out.

Creating Patches

To create patches you need 3 or 4 splines that intersect or nearly intersect. I soon figured that I got best results by using snap to points and snap to splines to edit my splines. If the splines are too far apart your patches aren´t that good. Here´s a couple of examples that achieve the same result and demonstrate how patches are created. I´ve circled where the spline points are so that they are easier to identify.

Creating Patches

Creating Patches

In the above image I´ve created virtually the same patch with 4 linear splines each. I used the Patch Creator tool to automatically create the patches. More on that soon. This shows that the patches are created where the splines intersect not necessarily where the points are. I think it´s useful to go through this so that you get a feel for how patches are created. Like polygon / box modelling you´ll get best results by keeping your patches 4 sided but it does cope with 3 sided patches pretty well. Recall that with 3 sided polygons you often get smoothing problems under a hypernurbs object or phong shading problems.

Okay now that you´ve seen how patches are created using splines let´s look at the process of the how the patch is created. There´s a number of ways once you´ve created some splines using C4D´s various spline tools:

1. Classical method - Create a Spline Patch object from the plugin menu and manually drag your 3 or 4 splines beneath it. These have to be arranged in clockwise sequence as they appear in the viewport.

2. Standard method - Select the 3 or 4 splines and then select a spline patch object. A patch is created with instance objects that reference the original splines as child objects. The original splines are then available to use in other patches. Apart from being able to use the splines to create other adjacent patches there is no need to have the splines in any specific order in the Object Manager.

3. Patch Creator - This came in SPLINEPATCH 2. Selecting this tool you are given a tool that´s very similar in operation to the close polygon hole tool. As you move the cursor around your splines a ghost patch is shown that represents where a patch would be created if you left click. Generally this works quite provided your spline cage has been constructed well. Sometimes however no matter you do you just can´t get the Patch Creator to select the right splines. There´s a number of fixes for this. The first up is to hold down the shift key and drag around the spline. I found this only worked sometimes. Next up you can revert to the standard method of creating patches and do it manually. Then lastly you can tidy up your spline mesh and or add in additional splines. I found sometimes getting inside the model and looking outwards worked quite well. I then had to reverse the normals of the patch. The patch has a range of options, one being to reverse the normals. I found for things like aeroplane wings that you can´t just draw a spline in the shape of the ribs and then use the Patch Creator tool as it has lots of trouble picking which part of the spline to use. In this case I found by making the rib splines in 2 pieces worked much better. You then need to hide the splines making up the the bottom of the wing whilst creating the patches for the top surface of the wing.

Editing Patches

If your spline cage is nice and uniform you can then select all patches and just click on the Multi Patch object. This single click makes all of the selected patches child objects and welds them together. Hopefully making a nice smooth surface. Sometimes however the patches need some editing particularly if the spline is very long. In this case the patch may be connected to the right spline but the 3 or 4 corner points may be in the wrong place. Each patch object has range sliders for each corner point that you can slide around to get the corners right. In addition to this you can adjust the ranges interactively in the viewport by dragging on little handles. To help identify each corner point there are optional symbols i.e. A, B, C & D for each corner. Below is an example where I´ve created patches with the Patch Creator tool and deliberately messed up one corner of the patch. To fix things up you can either drag on the interactive handle in the viewport or drag on the slider in the parameters. You don´t usually have to do much much editing if you´ve done things right but the tools and options are there if you need them. I found the more I used SPLINEPATCH 2.5 the better I got at building spline cages that allowed for easy patch creation.

Editing Patch Ranges

Editing Patch Ranges

Patch objects have lots of settings. These settings can be a little overwhelming but the manual explains what they all do and often you don´t really need to bother with them and once you´ve used the settings a few times they become quite straight forward. So long as your patch looks okay in the viewport you really don´t need to do much else. Other settings include reversing the patch orientation, centering the axis, reversing the sequence, selecting individual splines that make up the patch and more.

Multi Patches

After you´ve created some patches you have to join them together. The reason for this is to make the surfaces smooth between the patches because of the phong shading. The patches still remain separate and you can still modify the source splines and the patches and multi patch will update. The easiest way to connect your patches with a Multi Patch is to select all of the patches you want connected and simply select the Multi Patch object from the menu or toolbar.

Let´s have a look at a before and after shot to demonstrate what the difference between having a multi patch object and not.

No Multi Patch Object With Multi Patch Object

No Multi Patch Object                          With Multi Patch Object

Further smoothing can be obtained by either dropping the Multi Patch object under a hypernurbs object or adjusting the resolution of the Multi Patch object. Just like the Patch objects the Multi Patch object has a range of options and clever things that it can do. First up you can use it to globally control resolution of the individual patches. Much easier than doing this individually. Patches can be untriangulated and UV coordinates generated if need be. There´s a range of display options to display or hide inner and outer edge mini legends. More on some of these shorlty.

By the way, if I scared you off before with the spline range editing. If you build a reasonable spline cage like the mouse here then no adjusting of patch spline ranges is required. Creating the patches was done in seconds.

Like patches, multi patches can be made editable and transformed into regular polygons. Prior to this they are pretty much the same kind of surface as what other nurb type objects have. With individual patches you can control the resolution of them but best practice is to control them globally from the multipatch object. Like most things with the plugin, there´s a range of options for doing this. There´s so many settings for Multi Patches that I can´t possibly cover them all in the review. Here´s a screen grab of most of the settings. So many that I had to create 2 Attribute managers to show them.

Multi Patch Settings

Multi Patches - Settings

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