Something beneath your skin?

OK time for the next tutorial, I'll try to shorten the days between each. Today's topic, how to make something beneath your skin, behind a way, under the floor, basically a bump beneath something else.

I couldn't find a movie i could dl, so enjoy the link as an example of what it will look like as a finished product. While this may have been made with after effects, 3D will make it more realistic, as would any decent animation.

You'll want to start off by making a grid, this is for the surface of the object that will have the bump beneath it. Of course this is only an example, so it doesn't have to be a grid, it can in the shape of whatever you want, be it a wall, lamp, tree, persons skull or whatever takes your fancy. You'll want the surface to be high Polly, very high Polly to make the bump very smooth, I'm making mine fairly high, but not high enough, because as we all know the more poly's the higher the render time.

So now the we have the grid set up, we are ready to begin making adjustments to it for the final result. We'll change one of the views into a net view, this will automatically link us to a Softimage web site, full of free downloads, everything from models to scripts. Search for nulls, were looking for 'Add Nulls To Points', that's the script, now we wont click it right away, we'll change the left hand menu to the paint pallet, and drag and drop the script underneath the color chooses.

Now we have the script, we can save it and use it whenever we want. However the script as it is now is not what we want, so we'll have to edit it. Right click the 'Add Nulls To Points" button and select edit script.

In the edit script window, scroll all the way to the bottom, there you'll find the problem, you wont realize it at first unless you know C++, or know what your looking for. Original the bottom of the script looks like this.

End Select
'Create a Cluster Center
ApplyOperator "ClusterCenter", myCls & ";" & myNull , 0
'ApplyCns "ObjectToCluster", myNull, myCls

The ' at in front of the three features means whats on and whats not. For ever ' in front of the that means that command will be activated when the script is run, and the commands without the ' will not be done.

ApplyOperator "ClusterCenter", myCls & ";" & myNull , 0
'ApplyCns "ObjectToCluster", myNull, myCls

These bottom 2 are the problem, the one that is not selected will give us what we want, the one that is selected will create a small problem. We want the points to be constrained to the object, but the one that is selected will constrain the objects points to the nulls they are constrained to. So we simple change the two lines of script so they will now read;

'ApplyOperator "ClusterCenter", myCls & ";" & myNull , 0
ApplyCns "ObjectToCluster", myNull, myCls

I know it is a small change, but it makes a world of difference.

Were now half way through the process, the next few steps involve constraining and adjusting the points we have created. If you don't know the simples of constraints and the simple power they have of making our lives so much easier, this may be a bit hard to follow. Now there are 2 ways to do this from this point onward, we can use the implicit sphere or shape, or the mesh sphere or shape. Ideally we want to use the implicit sphere, if the shape you plan to use is more complex, i recommend using the implicit sphere and match the shape of the object as closely as you can, after all it will appear as a bump beneath the surface and does not need a high amount of detail. But first things first, we need to select all the points and make them a little bit more manageable. The easy way is to select one, and it will say something like Point_145, erase the _145, and type in *, so it will read Point*. * is recognized as xsi as wild card, so anything that starts with with point will be selected, this is handy for selecting a mass of objects, such as roots and effectors when need be. Now that all the points are selected, shrink them down so that they are more manageable.

Now while we have all the points selected will will constrain them positional to the grid. IT IS VERY IMPORTANT that you first check CnsComp and ChldComp, or else your points will converge on the center of the grid and pretty much be one object.

Create the implicit and/or mesh to use to interact with the grid. As i said earlier you should use and implicit sphere, but i will show you what happens when you use a mesh. Make sure the spheres are beneath the object you want to interact with, if its in the center, and points are inside the object, they will be stuck inside when you turn on the constraints.

The next big thing we run into is a problem with the constraints with the mesh and implicit, you can only select one per each, the bound plane for the mesh is not the right choice. It will preserve the distance between the points and create more of a block based on the size of the object, rather then deform itself around it, as it would with the volumetric.

Naturally we have the points selected to be driven , and selected the circle to be the deformer. Now we are done, and if you move the circle, whatever your choice of mesh or implicit, you will find if you made the right choice or not.

As you can see i did not make the grid high enough poly wise. But that is the way to over go how to make a bump on something.If you had any problems, questions or ideas for future tutorials please do not hesitate to email me at nik.chauvin@gmail.com.

XSI is a product of softimage there web site is http://www.softimage.com/

for more great tutorials on 3D http://www.graphic-tutorials.com/