File size increases greatly after do the collapse

[zhu.chao]

Hello Everyone,

I am drawing a crystal lattice consisting of atoms and bonds. The file size increases grealy after I do the collapse to the objects. Here is the details.

First, I draw the unit structure, which contains 4 objects of balls and sticks with materials assigned. The file size is 4,044 kb.

Then I do the ProOptimizer to all the 4 objects, which decreases the file size to 828 kb. (see the ProOptimized unit before array.png)

Then, I make an array of the unit structure, which contains 760 objects. The file size is then 920 kb. (see the array before collapse.png)

Since I need to use the array as a whole in another scene, too many objects are messy. So I use the Collapse to make the objects with the same material into one object. (see the array after collapse.png) The file contains 4 objects after the collapse. But its size increases to 22,484 kb.

So my question is why the file size increases so much after the collapse. Is there a way to decrease the number of objects without increasing the file size? Or is there a convenient way to use the array as an entity for designing in other files? 

Thank you

chao

[Anonymous · Accepted solution]

I really don`t know why you are concerned about file-size here, you should rather watch for RAM usage, but anyway:

Let`s do some investigation here:

1) Create a Sphere with 200 Segments. Save the file->708kb

2) Collapse the Sphere to editableMesh. Save the file->2416kb

3) Put a ProOptimizer on top of the sphere.Reduce to 10% vertex count. Save the file->2420kb.

4) Collapse the Sphere with the ProOptimizer.Save the file->812kb.

So why is that?

1) We are just storing a parametric object, and for it to recreate 3dsmax just needs parameters like radius,segments, transform ond so on. But it doesn`t need to store the mesh data, like vertex-, edges-, face tables. The mesh is created on the fly by 3dsmax using the stored parameters.

2) Since we collapsed the sphere here, we are now saving actual mesh data, all the vertices, face indices,...

3) We put a ProOptimizer on top of the mesh and reduce the mesh data to 10% of the original data. But the file size is bigger? In 3dsmax modifier stack data flows from bottom of the stack to the top. So it takes the incoming sphere mesh data and reduces the mesh data to 10% and outputs this to the viewport. The point is that the original mesh data is still there in the scene.It just gets processed by ProOptimizer.

4) After the collapse the actual 10% mesh data only is saved resulting in a much lower filesize.

5) Additional information: EditablePoly needs more information to store then EditableMesh.

Since you are only dealing with Spheres and Cylinders i would try to keep them as instanced parametric objects.

Hope that clears it up a bit.

[zhu.chao · Accepted solution]

Hello @Anonymous, thank you for the reply. It is very clear.

I tried to collapse the ProOptimizer and the Editiblemesh and the file size did decrease from 22M to 15M.

I also tried to make the array in types of copy, instance and reference. I found for the instance and reference array, the file size doesn't change much. But for the copy array, the file size also increases greatly.

So I think apart from the increasing due to the mesh data, the collapse also makes the array into seperated items, which requires more information than the instance or reference array. Is it correct?

[Anonymous]

Yes, unique meshes require more information to store than instances or references. An instance is basically a pointer to the original object but with an unique transform.