Project Working on my first addon

[orb]

Could I ask you some questions anyway? I have quite a few, and I can provide screenshots of my problems. The more I think about it, I realize that some of them are sort of generic problems.

Sure, either here, or you can PM me.

 

[Shadow Addict]

Hmm, I'll ask them here so anyone who sees this can answer. I'll start with two that both stem from the same picture.

The fins (which I've separated on the left) are all copied from one plane object, which I copied and placed around the body of the rocket. Pretty much after I'd placed them all, I realized that they had all become one object (that is, it moves as one objects, scales as one, rotates as one, etc). That means that the only way to edit one fin is by selecting all of the vertices or edges of one fin, and that gets tedious. Is there a way to separate them?

The next problem is on the engine bell, also visible in the picture. When I Set Smooth on that and a lot of other things, I get those strange black lines on the objects. They don't show up when I render it, but it's annoying when I'm working with the objects. Any idea why?

 

[orb]

For separating parts of object from that object, enter in edit mode and face select mode, select faces you want to create new object from, and press "P" key then choose "Selected" (or from context menu: Edit -> Vertices -> Separate). After that, selected faces will become a new object.

As for engine bell issue, I'd need to export something first to Orbiter, to check that out, since I don't know how smoothing is exported to Orbiter mesh. I may try later, but for now I think it's something wrong with normal vectors of vertices. How many sections has the cone of engine bell? Any texture applied to it?

 

[Shadow Addict]

Ahh, thank you so much for that!

Uh, it's got 42 faces, if that's what you mean. Now that I look at it, I see some of the black lines follow the borders of the faces:

 

[orb]

Now that I look at it, I see some of the black lines follow the borders of the faces:

I just modeled something similar from a cylinder and cannot replicate this issue. I don't know what you did here. Does it look right when you remove smoothing? Maybe try recalculating normals?

 

[Shadow Addict]

It looks fine when I remove smoothing, and it's happened to a few non-cylinder objects as well. How do I recalculate normals?

EDIT: I'd also like to say again that it doesn't show up when rendering.

 

[orb]

It looks fine when I remove smoothing, and it's happened to a few non-cylinder objects as well.

(-snip-)

EDIT: I'd also like to say again that it doesn't show up when rendering.

What other effects are applied to those strange displayed objects? Is anything changing when you switch workspace between solid/shaded/textured modes?
What graphics card do you have? Blender uses OpenGL for its interface, so it may be some problem with OpenGL drivers.

How do I recalculate normals?

I don't have Blender on the computer I'm writing now, so I can't remember correctly, but it's in edit mode somewhere in context menu, e.g. "Normals -> Recalculate normals" or something, but wrong normals would be also visible on the rendered image.

EDIT: Googled it for you -

Ctrl + N = Recalculate normals outside (you might have to select faces before doing so) Shift + Ctrl + N = Recalculate normals inside

These two hotkeys are useful when you extrude some edges and see a kind of seam in between (due to normals pointing in different directions).

 

[Shadow Addict]

Hm, strange. Recalculating normals shifted the lines and got rid of most of them, but they're still there. I'm running on a crappy laptop graphics chip that's had problems with OpenGL before, so I wouldn't be surprised if that was the cause (though it'd be disappointing if I couldn't fix it).

---------- Post added 01-29-10 at 08:17 AM ---------- Previous post was 01-28-10 at 10:53 AM ----------

If that's just a driver issue, then I guess I can live with it. I've got other questions. Say I want to make some sort of tube going from the upper body of the rocket down to the engine bell, following the contour of the rocket (as in the red line I drew in to the following picture):

I tried using a cylinder that I loop cutted, but it didn't give me the result I was looking for. I want to make a sharp bend in the cylinder that fits the angle at the bottom of the rocket. How can I do that?

 

[orb]

I tried using a cylinder that I loop cutted, but it didn't give me the result I was looking for. I want to make a sharp bend in the cylinder that fits the angle at the bottom of the rocket. How can I do that?

Have you tried to use a curve modifier for it?

 

[cjp]

Have you tried to use a curve modifier for it?

I have a less advanced method, which is probably more suitable for simple shapes:

First I made a simplified version of your rocket:

Next, as a starting point for the tube, I added a cylinder:

I entered vertex edit mode (Tab key) and selected the bottom vertices (there are nice selection tools available by pressing B once or twice). Note: as you can see, my cylinder has only 8 sides. I don't think a detail like this needs more vertices.

In the next steps, I extrude the bottom side of the cylinder (E key; I used the 'Region' extrusion option). By default, the extrusion function lets you translate the new vertices. I cancelled this (Esc key), and chose to rotate them (R key).
In the following screenshot you can see how to start the rotation. I am rotating around the 3D cursor, and placed the mouse right below the 3D cursor:

I started the rotation in this way for a reason: it allows me to place the points exactly orthogonal to the bottom part of the rocket:

An extra extrusion (this time we do translate the new points), and the bottom part is finished:

For the top part, I did an extrusion of the topmost vertices of the cylinder. Again a rotation around the 3D cursor. This time, the goal is to make a 90 degree corner in 4 parts, so it is important to make the rotation angle about 22.5 degrees:

Repeating this a few times (extrude and rotate), and the corner is finished. The last time rotating, I aligned the selection with the side of the rocket:

As a finishing touch, I did a final extrusion, to make sure that the tube enters the rocket:

After smoothing the shapes (in vertex edit mode, select all vertices (A key), open the special menu (W key) and choose 'Set Smooth'), the result looks like this:

Conclusion: extrude is my favorite tool. I do most of my editing with extrude, different modes of translate, rotate and scale, and a few special functions, such as merge.

 

[Shadow Addict]

Wow, that's incredibly helpful. I knew about translating with extrusion, but I had no idea you could rotate the points like that! That's just what I needed!

EDIT: I tried out the method, and I can't seem to rotate the extruded points properly. The center of rotation is in the middle of the cylinder when I have all of the point selected, not on the side as yours is; how do I move it?

 

[cjp]

EDIT: I tried out the method, and I can't seem to rotate the extruded points properly. The center of rotation is in the middle of the cylinder when I have all of the point selected, not on the side as yours is; how do I move it?

You need to change the pivot point. This can be done individually for each window. If you look at my 8th screenshot, it is the second button to the right of the "Edit Mode" button.

The pivot point needs to be set to the 3D cursor. Also, you need to place the 3D cursor at the right place by left-clicking where you want it to be.

 

[Shadow Addict]

Ahh, got it. Great, thanks! Here's my next problem: you can see the connected edge of my fin here

I believe I made it out of two plane objects with connected faces. However, when I subsurf it, it comes out like this, sorta split:

Is there any way to fix that? Should I just use some method besides subsurfing to get the desired smoothness and curve?

 

[cjp]

I don't really understand how you connected the two sides, and (more importantly) what end result you have in mind.

 

[Shadow Addict]

I connected them by selecting the edges and pressing F. I was trying to make a fin for the rocket that wasn't just a single flat plane object (i.e., actually having some depth).

 

[cjp]

I did it this way:

First I created one side of the wing. I did this, starting with a square, with extrusion, manually moving some points, smooth subdivision, and some fine-tuning of vertex positions to get a wing-like profile:

Next, I duplicated the entire mesh, and mirrored it. There may be a smarter way, but I did the mirroring by applying scaling with a factor -1 in one direction. See below on how to apply such non-uniform scaling.

After placing the two halves against each other, there still is some small gap between them. This gap can be eliminated by moving the shared vertices toward each other. First select them:

Next, to move them toward each other, we'll use non-uniform scaling again. This is how that is done:

• Select the appropriate view and pivot point (as in the screenshot below). I maximized that window with Ctrl+down to have maximum mouse range.
• Place the mouse as far to the right of the model as possible.
• Press the S key for scaling.
• To indicate the direction of the scaling, move the mouse to the left.
• Press the middle mouse button (or the mouse wheel). This enables non-uniform scaling mode in the axis direction that is most similar to your mouse movement.

In this case, we want them as close as possible, so move the mouse onto the pivot point. Repeat this scaling a few times to put the points firmly together.

The shared vertices are then still different vertices for both sides, which just happen to be on the same positions. If you want a sharp edge in the shading, then it's probably better to keep it that way. Otherwise, there is a 'remove doubles' function in the 'W key' popup menu. Maybe you can make a nice effect by merging the points on the sides you want to be 'round', and keep the points separate on the 'sharp' sides.

 

[Shadow Addict]

It's been a week and I just now am attempting this. My first try went pretty badly. How do you subdivide into triangles like that?

 

[cjp]

It's been a week and I just now am attempting this. My first try went pretty badly. How do you subdivide into triangles like that?

This is how I did it. Numbers refer to the image below.

A. Basic outline

• Add a plane and stretch it, so that it forms rectangle 1,3,2,4.
• Select points 3,4 and extrude to the right. The lowest point will form point 7.
• Move down the topmost extruded point, so that it reaches the position of point 8.

B. First subdivision

• Select points 4 and 8, and select (W key) -> subdivide, to create point 6.
• Similarly, subdivide the line between points 3 and 7.
• Subdivide the following vertical lines in the same way: (1,2), (3,4) and (5,6).

C. The trick

• Select all points
• Press Alt + F

This is the 'beauty fill' function. It tries to automagically find the most beautiful way to connect the selected points with lines and faces. If the points are already connected (our case), then the faces will be replaced by the new ones.

Before the next section, you might already want to move some points into the 3rd dimension, to get a rough idea of the 3D shape of the wing. The subdivision creates a lot of extra points, and if the rough shape is already in place, the new points will also be placed more or less correctly.

D. Second subdivision

• Select all points
• Select (W key) -> Subdivide smooth

Now it's time to fine-tune the 3D shape. It's convenient that our mesh subdivision has vertical lines, because in a perpendicular view, these can be turned into something that looks like a wing profile.

The number of points is not enough to make it really good, but I don't think that's necessary for details like fins. For aircraft wings, you probably want additional subdivision levels.

 

[Shadow Addict]

Okay, Mardi Gras break has given me a bit of time to work on this. I think I got the fin-making down, and I can't thank you enough for the incredibly detailed descriptions. I'm remaking my rocket with the skills I've picked up in this topic, and it's going way better. I'm beginning to think that subsurfing is a flawed method of smoothing, seeing as it tends to give me strange results. Just using Set Smooth often isn't enough. What is the best way to smooth things?