Continued
Welcome back. Are you ready?
Reference/anchor/pivot point.
Remember all the big numbers in the Global shift/scale dialog?
The numbers in the big box, is the placement of the reference/anchor/pivot point, in the file you open.
The numbers in the small box, is the placement of the reference/anchor/pivot point, in the file while you work.
The Global shift information is discarded, when exporting to .stl, so the reference/anchor/pivot point, coordinates will be the numbers from the little box.
For landscapes I prefer to have the pivot point, in the center of the model. It makes it easier to cut the model into managable pieces and reassemble them.
Moving reference/anchor/pivot point.
- Select the file
- Chose Edit
- Chose Edit global shift and scale
- Change X, Y, Z values to zero. Keep the scale.
- Hit yes
- Click Point picking in TTB
- Click on the point in the cloud, where you want the center to be.
- Write down X, Y, Z values. Click discard
- Select the file
- Chose Edit
- Chose Apply transformation
- Go to Axis, Angle pane
- Enter your written values, in the Translation section. You may need to check Apply inverse transformation.
- Hit Ok
Export test mesh
- Select the file
- Chose Edit
- Chose Mesh
- Chose Delaunay 2.5D (XY plane) (Until now I have left Max egde length at default)
- Select the file
- Save as Binary .stl file.
Open the exported .stl in Blender and check, if it is where you want it.
When you have it right, do another backup.
Very important!
Whenever you reload your centered cloud, do NOT! Shift the global scale!
Your choise should be:
Chosing the level of the cloud, to convert to mesh
- Select the file
- In the DB Tree Properties SF display params window, You can play around with the 2 circles until you only have the ground. (With the files I have, 2 is the ground)
- I find it easier to uncheck, show NaN/out of range values in grey, on the parameters pane.
- Chose Filter points by value in TTB
- Change both fields to your SF display params ground value
- Hit Ok
- Select Mesh and save. (I usually ad the levels to the name)
Creating a full resolution Mesh and export(This works for me)
- Select the file
- Chose Edit
- Chose Mesh
- Chose Delaunay 2.5D (XY plane) (Until now I have left Max egde length at default)
- Select the file
- Save as Binary .stl file.
Full resolution vs reduced resolution.
I found that in cleaning a full res mesh in Meshmixer, I was reducing the areas I worked with about 70-90%. It is much easier to reduce the cloud, before creating the mesh.
This however have the disadvantage, that the terrain details is washed out. (Not as sharp as with the full resolution cloud).
I have decided to keep the full poly mesh and creating a low poly mesh over that.
It does however slows down the PC.
My solution is to cut the full poly mesh, into chunks that I work on seperatly. This is way more easier in than in Blender. At least from what I know. More about this below.
Creating a reduced resolution Mesh
- Select the file
- Chose Edit
- Chose Subsample
- Move the slider from small towards large, remember your setting, hit ok
- You can delete the resulting layer, without touching the base layer.
- Play around with this until you, are sattisfied with the cloud density.
- Select the file
- Chose Mesh
- Chose Delaunay 2.5D (XY plane) (Until now I have left Max egde length at default)
- Select the file
- Save as Binary .stl file.
Cutting a mesh into chunks
Delete everything in CloudCompare. Or as I do, close and reopen CloudCompare. (You did remember to save your progress?)
Open the .stl file you created above.
- Select the file
- Now use the Segment tool, to cut the mesh into managable chunks
- Keep only the parts you are working with visible
- If you have cut something, that should not have been, use the merge tool
- Save each part as you go
- Always uncheck the parts, you have exported
When you import the chunks, they are in the right places.
I have used the resulting files in Meshlab, Meshmixer and Blender.
I would advise to lock the Location:, Rotation: and Scale: settings in Blender
You are should now be ready, to continue in your favorite 3D program.
Some Blender information
Moving view close to the 3D cursor
Moving reference/anchor/pivot point in Blender.
I have kept this as it is usefull for other offcenter models.
When importing the mesh in Blender, you might find that the placement is off, to way off.
Chosing Yes to All for Global shift/scale, have seriosly reduced, the placement being off problem.
The following example, was with No to Global shift/scale.
This is not happening in Meshlab or Meshmixer, only in Blender.
One example is the model in the picture. Blenderunits from scene center:
Transform
Location
X=684203.25000
Y=6123295.5000
Z=55.56239
There are 6 cars in this picture, can you spot them?
The reason for this, is the Anchor/Pivot point of the model.
The Location coordinates tells, where in the world the Anchor/Pivot point is.
Move the pivot point into the model
The first step, is to get the 3D cursor, out to the model.
I had some trouble doing this. The 3D cursor would just not appear, when clicking close to the mesh. With the view back, on the center of the world, the cursor worked as advertised.
This is how I got it to work:
- Make sure that the model is selected
- Chose View Selected
- Change to Edit mode
- Hit A to deselect all
- Select a Vertex
- Change to Object mode
Now you should get the 3D cursor, when you click. Well at least I do.
- Place the 3D cursor, where you want the Pivot point to be.
- Chose Object/Transform/Origin to 3D Cursor.
Your model is no longer off the mark.
A fast way to move the model, is to change the Transform/Location values.
Transform
Location
X:684203.25000
Y:6123295.5000
Z:55.56239
Center of the world
X:0
Y:0
Z:0
Good luck.
If you have any questions, then do not hesitate to ask and I will do my best to answer.
Keep in mind that English, is not my first language.
Update history
24/1-2016. Important note added to, Move reference/anchor/pivot point section.
23/1-2016. Move reference/anchor/pivot point + splitting mesh in CloudCompare sections added.
18/1-2016. Found a quicker way to do it.
awesome ty!!!!!!!!!!!!
