Blender Mesh Import issue & Recalculate Normals

Hi All,

being a newbie of Blender (2.68a), I am trying to import a .obj file.
This model is made up of several (more or less 1 hundred) different meshes. And I may have other similar files to work on separately.

Take one of the meshes, it has one or more sides (made up of one or more surfaces) that are transparent if Display Mode is Texture.

It seems I can’t add URLs here but you can find many people in this and other Forums that suggest the following:

Try selecting the whole mesh (A Key) and switching to Edit mode. Then click “Mesh” and go to “Normals”, then click “Recalculate Normals Outside”

It is working though I found that REMOVE DOUBLES before recalculating normals is vital.

QUESTION: it is working BUT on the ACTIVE datablock (let me call it mesh) only! In other words, it seems that one can make just one active object in the Outliner; that is the only one having normals recalculated.

The documentation says:

There is exactly one active object at any time (even when nothing is selected!).

Am I missing on something? I’d like to select all meshes and run normal recalculation at once.
Thanks.

Recalculate normals works on meshes not objects so you therefore need to be in edit mode. This means you can only do this one object at a time.
Select all the obejcts
Join them to one object (Ctrl+J)
Go into edit mode and select all vertices (A)
Removed doubles (W / remove doubles)
Recalculate normals (Ctrl+N)
If you want to then split thos objects you can then press P and split by lose parts
Go to object mode, select those objects and reset their origins (in toolshelf use Origin button)

Thanks for quick reply.

Most steps run fine.

Some more help please:

  1. P | split by lose parts generates many more submeshes than originally. I suppose I’ll need to join them manually?
  2. what do you mean with “reset their origins”? Meshes have not been moved after splitting them;
  3. I am meeting serious difficulties in selecting multiple datablocks in the Outliner: Outliner is needed in Edit mode only I guess? I am trying to follow the Manual by selecting one item, LMB, dragging and release the mouse on another item but all items in the middle are not selected?

Thanks.

  1. what do you mean with “reset their origins”? Meshes have not been moved after splitting them;
    When you join objects the origin of the combined object is set to be that of the currently active object. When you split them the origin of all those split parts will still be at that same location. If you’re happy with that then fine.
  1. I am meeting serious difficulties in selecting multiple datablocks in the Outliner: Outliner is needed in Edit mode only I guess? I am trying to follow the Manual by selecting one item, LMB, dragging and release the mouse on another item but all items in the middle are not selected?
    If you want to use the outliner, box select objects (B) then RMB / Select.

Last 2 questions:

1
I see some meshes are subdivided into many submeshes while others remain joined.
Nothing I can do through Blender UI commands?

2
What if I script in python to make each object ACTIVE, run normals recalculations and move to next object. All objects should stay untouched (neither joined or subdivided). Is this viable (I don’t know much of the underlying API)?

Thanks

What if I script in python to make each object ACTIVE, run normals recalculations and move to next object. All objects should stay untouched (neither joined or subdivided). Is this viable
Yes, you should be able to write a python script for this