Drawing a 3D tree in AutoCAD (my way)
There are different ways to draw a 3d tree, this is my option.
This way consent you to draw the trunk using 3d objects like cone and cylinder and join them in an only object. Then you assign the texture to this and the trunk is done.
The difficult is to draw a convincing crown of the tree.
My way allow you to do this enough easily.
There's a problem: the time of rendering is very long: for one only tree I spend until 30/45 minutes in high resolution, in middle resolution less than 10 minutes.
As I write in the description, draw the trunk following the branches of a tree.
Join a big cylinder to draw the main trunk and little cylinders and cones to draw the little branches.
Use immagination to do this: draw the branches in every sides of the main trunk.
Download the crown of the tree of the species you want to draw or photograph it.
Use a photo editing program to remove all parts you don't want to see.
Erase the visible trunk leaving the smaller branches.
Change all parts inside the crown that are white, the holes between the leaves, in black.
Save the image and remember its dimensions.
In AutoCAD create a new Global material.
Upload the image in these sections: Generic, Transparency, Cutouts, Relief composition or that you have according the translation in your language.
For each section modify the scale dimensions making them the same of your image.
Set for no repetition horizontal or vertical.
In Generic and Trasparency set "fade image" to 100.
The material is ready to be used.
Draw a parallelepiped with the dimensions of you image.
Move it on the z-axis enough above the graound.
Place it almost centering the axis of the trunk.
Apply the new material to it.
Note that if you create a jagged region you obtain a better effect.
Set the thickness of your parallelepiped or region to 0.01 or less.
Do a polar array of the parallelepiped using the center of the trunk as axis of array.
I recommend you to set the number of elements of the array to 5 or 7 or 9, not an even number.
Than explode the array leaving the various parallelepipeds, or other objects you draw, indipendent.
Pay attantion that more are the parallelepipeds, more time you need rendering your draw.