View source for Assimp

[[Engine_Development|Development]] < [[Game_and_Unit_development|Game Development]] < {{FULLPAGENAME}}

=Assimp=
Open Asset Import Library (short name: Assimp) is used in Spring for loading a number of common and well supported model formats (.3ds, .dae, .lwo, .blend - currently .obj is parsed by a different code path).

What Spring supports in its Assimp renderer:
* extended metafile (<code>%modelfilename%.lua</code> next to the modefile)
* still uses tex1 & tex2 texture system of S3O (same shader as S3O)
* 2nd texcoord
* loading of the texture filepaths from the model (don't have to be in <code>unittextures/</code>)
* when texture filepaths aren't included in the model, it searches for <code>%modelfilename%.*</code> & <code>%modelfilename%2.*</code> in <code>unittextures/</code>
* special modelpieces `SpringHeight` & `SpringRadius` {{removed|101.0}}
* {{new|102.0}} auto-normalize normals and tangents for all AssImp-loaded models
* {{new|95.0}} allow modellers to work around {{mantis|3552}} (differing axes conventions between software) by recognizing a number of new piece-table keys as follows

For the root piece: {{removed|104.0}}
* "xaxis" = float3, "yaxis" = float3, "zaxis" = float3 (determine global orientation of model)
For all pieces: {{removed|104.0}}
* "rotAxisSigns" = float3 (determines direction of script-applied rotations around each axis)
* "rotAxisMap" = number (currently can only be 0=XYZ or 3=XZY, determines coordinate conversion)

=Assimp Textures=
See [[3DModels:Textures#Textures_-_Assimp_Model_Formats_.28DAE.2CMDL.2CMD3_and_others_except_OBJ.29 |3DModels:Textures (Assimp Section)]]

=Standard Workflow=
The following Workflow is provided for a standard 3D Modeling package using the Z = forward, Y = upwards convention, like Maya, Modo or Lightwave. You can also use Blender to export models for ASSIMP, as covered in the next section.

* [[3DModels:AssimpWorkflow]]
* [[3DModels:AssimpMetadata]]

=Blender Workflow Tutorial=
This is a stub containing a simple outline of a Blender workflow.

# Open an existing Blender model or import a different format through the File menu (File > Import). You can import s3o models - complete with materials - using the [https://github.com/sanguinariojoe/blender_s3o_import s3o import] plugin.
# Compose your model by making a series of rigid pieces, and parenting them to one another (ctrl+P). These will be imported as `pieces` into Spring.
# It is preferred to apply all scale transforms, because uneven transforms will not be tolerated by Spring. You can keep rotations, though.
# Blender is Z-up and Spring is Y-up. Spring will import Blender models as Z-up. If you want to fix that, add a root piece to your model, and rotate its children 90 degrees, such that their local Y-axis points up.
# Make sure you have a lamp in your scene while in this mode or your model will be dark. You can delete it before export.
# If you want to animate the model using the animation exporter [https://github.com/Anarchid/blender2lus addon] later, set the rotation mode for all your pieces to be Euler ZXY.
# Applying texture: 
## In the UV/Image editor, click the image icon (Tooltip: Browse Image to be linked) to select your texture. If it's not there, click on Image > Open Image to browse for it.
## In the 3D View, select (right-click) your object and hit Tab to enter Mesh Mode. You can select multiple objects if you want to unwrap the entire model without going piece-by-piece.
## Hit A to select all your faces.
## In the 3D View, hit A to select all the faces there and select your image with the image icon. Assuming there's a UVMap, you should see your texture.
## If you don't see any faces you'll need to add the UVMap to a new texture:
### In the Properties view click on Textures (checkerboard icon).
### Click on Add New Texture (plus icon).
### Select Type = Image or Movie.
### Under Image, click on the image icon and choose your image file.
### Under Mapping, select Coordinates = UV.
### Under Influence > Diffuse, check Color and make sure it's 1.00.
## To add a normalmap:
### Repeat steps 5.5.1 to 5.5.5.
### Under Image Sampling, check Normal Map.
### Under Influence > Geometry, check Normal. Make sure it.s 1.00.
## You'll need to do this for each piece.
# Piece hierarchy:
## Select piece A, hold shift and select piece B. Hit Ctrl+P and it will make piece A a child of piece B.
# Setting piece origins:
## Select a piece.
## Place the 3D cursor where you want the origin to be (left-click).
## Click on Object > Transform > Origin to 3D Cursor.
## You can now rotate your pieces:
### Click on the dropdown "Pivot Center for Rotation/Scaling" and select Individual Origins.
### Rotate.
## Do this for all your pieces.
# Preparing for Spring (this may or may not apply depending on how assimp handles your model.):
## Ensure that the scales for each object in your scene are uniform (that is, x, y, and z scales are equal to each other). A quick way to ensure that is select all (a) and apply scale (ctrl+a -> scale).
# Save your model.
# Select all the pieces of your model, ignore the lamp.
# Click on File > Export > Collada.
# Check "Export Only Selected" and export.
# The dae file will be used as your object.

Don't hesitate to google for answers if you bump into questions with how to use Blender itself. It's a powerful piece of software with a lot of tutorials on how to use - the scope of this article is not teaching how to use Blender, but only how to use Blender for making Spring models.




[[Category:3D Models]]