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Forums Maxon Cinema 4D Need expression, master, or multiple groups?

  • Need expression, master, or multiple groups?

  • Joseph M. Morgan

    July 16, 2007 at 5:20 pm

    I consider myself new to Cinema 4D, though I’ve done a couple of commercial things with it. I now have to build an entire stadium. As you might imagine, even the most basic form of this thing will have scores of objects…. but I plan on keeping it around and evolving it as necessary. Some objects I can manage effectively in arrays so I have a single object, and in others I can use instances.

    However, in some cases, right now with respect to lights, I can’t hierarchically manage them in a way it is easy to select them all for a consistent change. So I have this question:

    Is there a way to create a “master” light, and then “slave” a bunch of lights to its properties so I can easily change just the master? Consider, for example, turning on or off all the lights in the stadium. They cannot be instances or arrays for this case… so it would be cool to simply be able to set all thier brightness to 0% at once. In other words, how do I make only the “brightness” property act like it would in an instance?

    or… is there some kind of expression (like in after-effects), to effectively parent a property to a property or expression of another object ( same concept as “master-slave” just a different way )?

    or…. is there a way to create multiple groupings… that is, for the field lights, there are multiple bars of lights and fixtures needing different angles, but similar brightness. Can I create one group for the angles, another for the brightness?

  • Alejandro Torres

    July 16, 2007 at 7:36 pm

    Do you have moGraph? that would be the easiest way…

  • Joseph M. Morgan

    July 16, 2007 at 8:05 pm

    Unforunately not… do you think it is cost effective for what I’m describing?

  • Brian Jones

    July 16, 2007 at 10:47 pm

    easiest way (because it writes it’s own xpresso) is to right-click on whatever property you want in your master light and choose Animation/Set Driver then choose all the lights you want to follow it then right click on the same property and choose Set Driven (probably Absolute in this case). If you look in the xpresso tags it makes you will see what’s going on and really one expression could do the whole thing with the driver light linking all the properties you want to control to all the driven lights. Check this example, it’s done both ways described as above for both only Intensity and color are controlled but it can be anything that is controllable.

  • Adam Trachtenberg

    July 16, 2007 at 11:42 pm

    Another option is to use a Selection Object set up to select all of your lights. Then you can adjust whatever light properties you want for all of them. You can adjust properties either absolutely by simply typing in a number or moving a slider, or you can change them in a relative fashion by typing in the numerical field, “x*[]”. For example, if you wanted all your lights to be 1/2 as bright, you would type in “x*.5”.

  • Joseph M. Morgan

    July 17, 2007 at 12:04 am

    This is the first time I’ve seen XPresso. I got how you did the “Set Driven” example, and was easily able to add Contrast to the set as well.

    However, I can’t figure out how you did the “One Expression” one. I opened the XPresso editor… but can’t figure out how to add something. I can easily delete a “port”, but I find no way to add one.

    The “Set Driven” seems more “Cinema 4Dish” to me… but, in the interest of learning… how do I get the “One Expression” thing working/edited?

  • Joseph M. Morgan

    July 17, 2007 at 12:31 am


    My brain is in “After-Effects” mode on this… which may be part of the problem. I’m trying to pick-whip things to each other, add just properties to the selection object… by dragging them ( I tried every variation of dragging I could think of… which may indeed be one short… but still not getting it).

    I’m missing something fundamental. I successfully added 3 sample lights to the selection object… and thought, quite stupidly… that would be that.. and I changed the color of one. It, of course, didn’t change a thing in the other two. C4D allows me to hierarchically add the lights underneath the selection object, but somehow I don’t think the design of the selection object is meant for that.

    Is this something useful only in animating?


  • Brian Jones

    July 17, 2007 at 2:34 am

    First, what Adam means by using a Selection Object is to put all the lights you want to control in a Selection Object (a collection of things you want to select/deselect all at once) and once all the lights you want to control are selected you can change the properties of all of them at the same time. (too blindingly obvious for me at the time 🙂

    The xpresso ‘One Expression’ thing. The easy way to get objects (well, a reference to the object) is to drag it from the Object Manager into the XPresso. In this case I selected the 3 lights and dragged them into the XPression window I had attached to the null (it doesn’t have to be attached to the null – any object in the scene will do, it just makes sense to attach it to something related to the task).
    To add a port on the left (input by default) or the right side (output by default) is to left-click on the blue or red square in the upper corner and choose the property you want to input or output.
    XPresso is pretty deep but it doesn’t take much to do useful stuff.

  • Joseph M. Morgan

    July 17, 2007 at 2:56 am

    OK… cool. I am so dang tired… you know what… must have clicked everywhere in the danged window and on the objects “except” there.

    I still don’t see how the selection thing works… are we actually talking about a selection object, or a null? Nevertheless, I like the one expression thing better anyway. I will be playing with the “Set Driven (Relative)” as well… as that seems interesting.

    Thanks for your help… I did rethink some organization and managed to reduce the actual number of light “objects” to 3… so that made it much easier. It didn’t orignally dawn on me that “instance” just meant the same thing in a new location/orientation… and that these “instances” could cross hierarchies… I’m making things way too hard on myself.

    Thanks again.

  • Joseph M. Morgan

    July 17, 2007 at 3:03 am

    Oh… I got it… Thanks.

    I couldn’t figure out how the Selection object enabled the selection… the “Restore Selection” button didn’t make sense to me… My brain would have wanted it to say something like “Select Attached” or some other language that I’m sure no one else but be would get 🙂

    Thanks… useful…. and I suspect I can create multiple selection objects… like “off”, “on 50”, and “on 100” such that all lights are connected to “off” and I can set the brightness to 0. When the lights need to be back on, the “on 50” can be used for those lights with 50% brightness, and “on 100” for 100% brightness. Ideas are coming…



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