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Blender modeling question
Trojan0
Posts: 0Member
Blender noob.
I decided to model the 1st Death Star. I create a UV Sphere, create a cone, and boolean difference the cone from the sphere for the laser dish.
When I do this, I generate mesh errors that get these nasty triangles around the circle. Doesn't matter what I do. I use UV Sphere, I use Icosphere, I try to use a difference modifier (which about kills the program).
How do I model something as simple as the friggin' Death Star? The errors only show up when spoothing is activated. Solid shows every stupid flat.
Chris
I decided to model the 1st Death Star. I create a UV Sphere, create a cone, and boolean difference the cone from the sphere for the laser dish.
When I do this, I generate mesh errors that get these nasty triangles around the circle. Doesn't matter what I do. I use UV Sphere, I use Icosphere, I try to use a difference modifier (which about kills the program).
How do I model something as simple as the friggin' Death Star? The errors only show up when spoothing is activated. Solid shows every stupid flat.
Chris
Post edited by Trojan on
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From everything that you've said elsewhere however, I'd say that you need to follow some tutorials and learn the consequences of smoothing and smoothing groups.
I'd say that you've got a sphere with a cone shaped indent in the side, all attached together, then smoothed with the expectation that the cone is going to have a nice crisp edge to it.
Unfortunately, that's not going to do it - you either need to separate the cone and sphere into two different smoothing groups, or introduce a whole load more polygons around the cone to create a smooth transition between the two. All you are doing at present is asking the application to try and smooth between two (actually more) surfaces at dissimilar angles and axpecting it to get it right without any hints as to what you want it to look like.
In particular look at basic modeling tutorials and creating smoothing groups.
Actually, what I am doing is subtracting the cone from the sphere. When I remove the cone (delete, or move it) there is a dent left behind from the cone. Right on the edge of the spere- where the cone was- is where the errors show up when smoothing is turned on.
I'm coming from Truespace, and admittedly, it's been about 6 months + since doing any 3D of any kind... and that includes the Blender tuts. I guess that's what I get...
Chris
[Edit] Sorry, I think I misunderstood your problem...
In this case, have you considered going with the flow? I'd suggest that you put the Death Star's laser dish at the north or south pole of your UV sphere. Delete the rings of vertices until you have a hole equal in diameter to the laser dish, then connect the rim vertices to a central point to make the dish.
Finally rotate the UV sphere to put the dish at the proper latitude. Granted the Death Star's north and south pole will not correspond to the poles of the UV sphere, which may be a problem if you are going to actually cut trenches into the sphere instead of using textures.
I had actually considered doing *exactly* what you did... but the trench is what held me back. I just *know* that if it's not the dish that causes problems, it'll be the equator trench.
I have a couple other things in mind... isn't there a mapping method that actually alters the geometry? I believe there is... but I dunno if it'll do what I am after.
Chris
"Normal" mapping paints a Trump L'Oeil image of the bumps with shadows on the flat surface. It does not actually alter the geometry. The advantage is one can work with a low poly model. The disadvantage is that if one aims the camera across the surface, the render will reveal that the surface is actually flat.
Manual/Bump and Normal Maps - BlenderWiki
"Displacement" mapping actually alters the geometry. The advantage is that the geometry is really altered. The disadvantage is that the resolution of the bumps is limited to the density of the vertices, which means unless you have a high polygon surface, it looks crude.
Manual/Displacement Maps - BlenderWiki
An example I did of displacement mapping:
But then again, if the geometry is a high enough resoultion, then the displacement map might be un-necessary, and a guy could model the details without the mesh errors that show up in smoothing.
Here's another thought: create a profile of the sphere with the cone removed, and lathe - revolve- the planet with the centerline going thru the center of the dish. Might not be able to boolean the equator, but perhaps the displacement map might help in this circumstance.
You'r a good guy; thanks for your help and patience.
Chris
However, I see some undesirable effects around your dish area- but nowhere near as bas as what I've been getting.
Chris
But what i do when i boolean is to make the boolean cut, but keep a copy of the orignal mesh. Then join the 2 meshes so you can edit both of them so you have the vertices in the right spot and just hand fill it in.
That aside, is boolean-ing even the right way to go about this?
Chris
it will be the fastest way, but not the cleanest way. I dont really know how else to do it
Next best thing (if you are not oriented around a pole) is to create a single plane cutting through the sphere at the angle that you want and use Knife-cut rather then booleans - a 2D oriented cut will always be much cleaner that 3D. - from here-on, just grab the polygons around the cut area and extrude them into the shape that you want.
If you want to ensure that you are extruding along the correct plane, just patch the hole first witha flat series of planes and make sure that you are extruding along it's normal.
As I've said before in this thread however, all of these different methods of cutting are not going to help you if you are still asking Blender to smooth around that edge. Its not the cleanliness of the cut that is causing your smoothing abherations, it's the complexty of the circle and the angles around which you are asking the smooth to take place - you need the join between the sphere and cone to be made out of many more polygons than just sphere+cone - you need to guide that edge around the angle if you want it looking perfectly smooth.
First I'll say this, I'm still learning after three or four years, so don't think I'm an expert. Some of these guys know way more than me.
Second, I will tell you what I did. I started with two spheres, one large and one much smaller. I positioned the smaller of the two in the location I guessed the dish would be located. (mind you I was just experimenting to see waht would happen) Next I switched to Object mode and selected the larger of the two spheres. Holding the shift button I selected the smaller sphere and the chose the boolean option ("W" key for the shortcut) and chose difference. The new object is not highlighted so I simply moved the old objects to a different layer. I then chose the new object and entered edit mode. Using the "A" key shortcut I highlighted the entire object and clicked the auto smooth button. I then clicked the set smooth button about ten times and rendered a picture.
It might not be perfect, but it could get you started. Anyway, just trying to help.
did you ever get what you wanted or you still having trouble?
I put it on hold for the time being because I caught wind of a short film contest, which I am almost done writing for.
The film deadline is the 16th... so maybe on the 17th or so I'll give it a try again.
Chris
a small tweak and you can model the verticle trench as well...
this was done with a icosphere, so getting straight lines is abit hard...but i think this same thing can be done in uvsphere just not sure how just yet...