Now we can actualy select individual poligons. After we select top polygon of our cilinder we find a tool called extrude alog spline, and select a spline. As you can see parameters are straight forward. Segments - repreent the number of intersections created in resulting mesh. To put it simply, the more segments the closer resulting surface will resemble splines shape. We dont whant to overdo the value, and usualy i would sudgest the number which creates the size of poligons sililar to the original cilinders polygon sizes. This will make models topology and the detailness well and equaly distributed alog model.

Align to face normals aligns the spline with selected poligons normal, or average of selected polygons normals, if we select more then one polygon for extrusion.

Other tools are very simple too. Just change the values and wach your viewport.

So, to make our tree more interesting we will be modeling multitrunked tree. Now we create a new cilinder which will become main trunk. The main thing to abserve now is the size, or better to say diameter of trunk. It shuld "go well" with other trunks.

Other thing to have in mind is sizes of poligons, again they shuld be similar size of other polygons in the trunk we created previously. Ofcource thats not that important, but its easier then models topology and flow of edges are well distributed,.

I agree this point could be questionable and some would consider it as a unnecsary restriction, so anyways, no rules are made so they could not be broken :)

Well, for me it is a issue of convinience and preference.

And then we procead with a steps already described. Creating a new spline, thinking of its visual characteristiks, editing it while it looks good and "pleases the eye" - thats a moust scientifick part of tree modeling, and who knows might be life in general :)

So, extrusion of the new cilinders top polygon along new spline. The result will probably not look exactly the same as spline itself, unles the bigining of spline will somwhat mech the cilinders top polygons normal direction. But its not engenering or architecture, so i dont see problem in that. Dont forget to rotate (rotation parameter in extrude polygon along spline dialog box) till result looks good.

We might end up with some problematick areas. As we see in a picture polygons intersect, and thats not something we would like to see. So after each "extrude alog spline" operation, it would be good to inspect resulting surface from all sides, and make sure mesh is all good.

Such problematick areas are easily to corect. Wy simply select edges which go thrugh other polygon and pul them up, well up in this case. we can do the same in vertex mode, its just harder to select vertecies which are "hiden" - which go thrugh model. If we whant to work with vertecies (it usualy alows grater control) we can try presing ant x, or was it crtl x - it makes model semy transparant, so you can see through. or presing f3 makes u see only vireframe. Untill model is reletively "low poly" its easy to navigate and edit it in vireframe mode too.

Next step will be, to create aditional edges around intersections of trunks. This we will do, in order later to be able to create one shape from two separate trunks.

Tips for max users.

Its better to cut edges in vertex mode, so you are certain where new vertecies will be created. Cuting in edge mode is good too, but one must be careful not to make a mess = small areas where you think its one vertex, but when u zoom in or select are, there are actualy two or more. It makes mesh untidy, and can later lead to some problems.

So we repeat creations of contour lines on bouth trunks. At this point lets try not to create lots of unnecesary details. keep it simple ( for now ). It helps for your sanity :)

Next step is to select all polygons which touch other trunk. Dont forget to look all around in all viewports, look at vireframe, and so on.

It always helps to "isolate" your object, alt Q for max users. Well idea is to hide other trunk so we can easily select all polys. Next we hit delete.

People working in older max versions or in other programs might not see the picture as it is showen in left. Here we see "insides" of polygons. In some aplications it is not a case, and we must make sure we see them, its just easier to work. One way is to apply "two sided" material, but this might be diferent in other aplications. You might look for options on displaying mesh in viewport. The word backfacing might help.

Look here and look for word backfacing in bold. Or do the same in your programs help files.

We repeat thuse steps with bouth trunks. Be exra ceareful and make sure you didnt created any acidental extra small pollys. Keep it clean. Then we will atach one trunk to another, as a result it will become one object. So we can edit bouth at the same time. Attach button is find under edit geometry.

Now we go to vireframe vieving mode mode (f3 for max) and select outlines of just deletead polys. As you can see the butom of tree was also splited. Basicaly now we have to have to edge selections, so in next step we can "bridge" and create polygons in this empty space. In other words we will conect bouth trunks.

So max users have this tool called bridge. I am sure all other packages have some exvivalent. In worst case you will have to manualy create polygons. That would be very time concuming... but :)

Again bridge dialog box has some parameters, which are easiest to understand by trying. If its first time you use bridge, it would be good first to play around with it on simplier model. For instance create two boxes, make them one poly object, select one surface in each box (chuse thuse surfaces which are in front of each other) and play with bridge tool.

So as you can see both holes in trunks have slightly diferent topology, diferent numbers of vertexies, therefore sometimes bridge doesnt produce best possible result. You will have to manualy tweek som vertexies to make sure result looks good.

After we cuted holes in our trunks and conected them, we must make sure we do not have some mistakes. We could have left some small polys strange edges and unnecesary vertecies while cuting, or we could have done something wrong while selecting outlines for bridging. The easy way to chek is to apply turbo smuth (mesh smooth for older max versions). Basicaly its max implimentation of subdivision surfaces. Everyone has them but some chuse to play with names a bit :)

So if we would have problems in our mesh after subdivisions are aplied we would see it much clearer. Basicaly subdivision algorithm "smoths" our object by creating much more polys. Well for better definition look at wiki.

So again we look at our model from all sides and see if everything is corect. If so we can remove mesh smoth, or make it inactive in modifier stack, and continue detailing tree.

Now we will create third trunk. We repeat all steps mentioned above.

If we are happy whith general shape of our new trunk, but some minore parts are unpleasent, we can corect that using another nice tool. Basicaly after u select polygon, in max, u can make it as soft selection, meaning other nearby polys will be slightly afected by what you will do to originaly selected poly. In picture we see rotation of poly, and how nearby polygons chage too as a result.

Again we do not forget to see if polygon extrusion along spline produced some problems. If so, as showen in image, we fix it ....

..boring.. :)

While creating outline where objects intercect, we dont forget the butoom of the tree trunk.

Nex we procead with a steps described earlier.

Sometimes our mesh becomes quite complicated and complex, so it becomes hard to navigate and edit.One way to make our lifes easier we will do the folowing: (again thats for max users, but others must have something similar)

1. we select our outlines, or in other words Borders, using max terminology.

2. while holding control button on keyboard we change our selection mode from edges to polygons. the result is edge selection converted to polygonal selection. This will be the selection of polygons we will work with, and we will hide the rest. Sometimes you can pres "grow" once or twice if you think you must see more while editing.

3. we find a button caled hide unselected, which is located in edit geometry, under other controls for poly editing.

The picture shows result of it. Now we see only selected polys and it easier to work with.

Here again we procead with already known tools. Lets conect parts of models by bridging.

And as always we do not forget to check our model if it has any mistakes by applying mesh smoth.