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View Full Version : PFlow pivot points for instanced geometry


TiskO
07-13-2007, 11:38 AM
Not sure if this is a bug, or im missing something here.

Im trying to build a library with approx 5000 books. That's fine, got all that in there, using a box (proxy for hi-res book) as the instanced geometry. The default pivot point for the box is the minimum, not centre (which is perfect).

Problem is, that i need to scale the books on the Z-axis randomly. I place a "scale" operator for Z-axis, and it scales the particles (books) as if their pivot point is in the centre, which it isnt. Now i have books going through the shelves and others floating. Is there anyway to correct this?
At present, the particles are being spawned on a selected edge, and i had to play with the surface offset to get them sitting on the shelf, otherwise the centre of the book was at the edge.

Next question...How do i produce a random gap between the particles (books)? For example, i want say.....6 books to be side-by-side, and then maybe a 15mm gap, and then more books etc etc. ive tried a "keep apart" operator but that was pointless, and ive also tried playing with the seperation distance in the "position object" operator (for the books), and have had no success with that either.

Anyone - Suggestions?

OlegB
07-13-2007, 03:16 PM
In the Shape Instance operator the pivot point is automatically shifted to the centroid (gravity center) of the book. You can circumvent it if you attach the book reference geometry object to a dummy (the dummy center should be at the original pivot point of the shape), and then use the dummy as the reference object for Shape Instance operator. Since the reference object is a complex entity (with a child) then the centroid offset is not applied.

The gap issue can be solved with Box#3.

Thanks,
Oleg B.

TiskO
07-13-2007, 04:07 PM
So, you mean to link the books pivot to the centre of a dummy? When i apply the random operator, that will mean that the dummy will scale, as will the book? is that right?

TiskO
07-13-2007, 04:08 PM
Don't have access to box3 :sad:

TiskO
07-13-2007, 04:18 PM
yeah that worked like a charm! Linking the box to the dummy - sweeet! Never even though of that! Thanks OlegB :thumbsup:

Now just for the spacing part...Any other ideas OlegB? Bobo?

Also, how do i apply a random materialID to each partcle? Ill need like 30-40 different matIDs....is that a box3 job too? Please tell me no..... :rolleyes:

OlegB
07-13-2007, 06:31 PM
how do i apply a random materialID to each partcle?
Material Static operator - read the reference in the 3ds Max Help.

Thanks,
Oleg B.

TiskO
07-13-2007, 08:26 PM
Thanks. Must have missed that one.

supremepizza
07-13-2007, 08:48 PM
Don't have access to box3 :sad:

If you don't have Box 3 Just copy Identical PFlows, varry the seed values etc. and decrease the number of particles due to using more particle systems.

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