I am trying to model one of our company’s products with Blender but I ran to problems from the very beginning. I have little experience in 3d and I have played a bit with Blender, but I am still a newbie with all these things.
I tried to start with a simple part of the product. A steel bar with beveled head and one hole. Here is simple crosscut of the part.
It would have been easy without the hole. I started with a cube, extruded one face and scaled it down to make a bevel. Then I subsurfed the whole thing, selected some edges and changed crease to make them sharper. I used crease value of 0.8 for filleted edges. The result was quite much what I was looking for.
Then I faced a problem. How do I add the hole? I tried to cut the hole to this low poly mesh with booleans. The result was not good and I thought I have to “bake” subsurfing first. No problem, I found the apply button. I cut the hole and there it is, but the mesh is now far more complex. And another problem is that I can’t subsurf it anymore, it becomes ugly around the hole.
I tried rendering. It was a bit blocky first so I pressed “set smooth” and another problem popped up. I have seen these odd jaggies (on the bottom of the part) before, but I can’t remember why they are here and how do I get rid of them.
So: How would you model this kind of simple part? I have used Rhino a bit and with Rhino this would have been easier for me, but I think it’s only because I don’t have too much experience with Blender. I want to learn Blender and I find this a great chance to start learning something.
The biggest problem is the hole. If I want to use a simple mesh and subsurf, can I make the hole or is the only way to “bake” the subsurf the way I did? But I want to add a little fillet to the edges of the hole. How can it be done?
Good tutorial links are appreciated also. I have read some, but have not found a solution to this simple problem.
Here is a picture showing the mesh of a similar problem. Basically delete some verts to make the hole and then add a mesh circle formed to the shape of the pipe in end view and filling in the faces between. If you are subsufing make sure you have 3 “rings” of verts called face loops around the hole edges – easy to do with extrude. If you make face loops around your edges you won’t get artifacts when subsurfing.
Well I think I can help you out. Those “jaggies” I believe are artifacts. Solution: in edit mode select the whole mesh and press ctrl and the N key this should bring out a window, just click recalculate all normals. For the hole part i don’t think I can help you on that, sorry. Any else wants to take a shot at it?
The problem you present is a classic illustration of the difficulties associated with modeling man-made/mechanical entities with a surface modelling app. However, I think you are on the right track with the methods you’ve tried. A couple of things I’d do different (I tinkered around a bit with what you’re looking at modeling just now…) would be to start with cylinder primitives (for the shaft & hole) and work from there, rather than to utilize a subsurved “block” primitive. I would also not necessarily “bake” the boolean - just leave it as a modifier - which I think can be subsequently edited to some degree (not sure). For the chamfer on the end and the fillets on the corners/edges, look to the knife loop-cut tool (K-key menu) and the Bevel Center script.
This kind of thing seems to happen when setting smooth on all faces. (of course, after you’ve done the ctrl-N thing that Cad2Blender mentioned) I’ve tinkered with set smooth and AutoSmooth to get these things ironed out in the past.
If you’re not adverse to using other tools for mechanical models, you might look at the free but somewhat limited Alibre Design Xpress. Its no longer an ad-supported app, and can do this kind of thing slick n quick…
Big thanks to everyone! First I thought to give up, download Alibre Design Xpress (Thanks for the link, mzungu!) or install my old version of Rhino. Maybe they are more suitable tools for this kind of project. But two things made me change my mind: I am using mostly Linux and both Alibre and Rhino are win-only. I could try them with Wine, but Blender works perfectly under Linux and I try to use open source software if possible. That’s not a big problem, I still have windows installed and so on… but the bigger problem is that I can’t render good looking pictures with Rhino. I don’t know if the free version of Alibre has better renderer, but my Rhino renders used to look like opengl previews. As I am trying to achieve a good looking visualization (and maybe animation) of the product, not a 100% precise cad model, Blender would do the job. Two good reasons to continue with Blender, but I still have two more. I said I want to learn Blender. I learn nothing if I give up. And Blender seems to have a good user community. I really appreciate your helpful and friendly attitude.
My render came out beatiful when I did that ctrl-n and AutoSmooth thing you suggested. One problem solved.
I played a bit with cylinder primitives and it looks quite promising. GreyBeard’s example looks very good also, thanks for providing the wireframe shots. I have to try that even if I don’t know any easy way to model the hole.
I think I will boot to Windows this night and try Alibre. It looks interesting. One way would be to model with Alibre and export to Blender if possible, but I’m afraid the resulting mesh would be quite messy. Maybe it’s better for me to learn basic modeling in Blender first and try this part only when I am familiar with the Blender way of modeling. So this can wait a couple of days.
sakke13, definitely try to learn how to model this with blender first! If you take the time to overcome such obsticles, then the rewards will be great! (esp. if the model doesn’t have to be dimension-precise, as you say…) Also, swapping between windblows and linux is a PITA!
You should be successful with this using STL output from Alibre. But, yes, the imported mesh will likely be much more messy than, say, Greybeard’s example above. (It’ll likely turn out similar to your boolean/subsurf example in your first post.) Take particular note of his use of edge loops (the extra edges near the part’s corners.) This is a very good habit to get in to.
Blender is a very flexible poly-surface modeler (tho it still lacks a couple of crucial features) which can be handy for pros, but frustrating when learning it. You might consider trying out Wings3D for modeling. I think it has linux flavors, and while less flexible than blender, has some more “automated” functions.
GreyBeard’s answers in this thread intrigued me and finally I solved it.
The problem was how to shape the circles. The solution turned out to be really easy but it took some time, however.
Create the basic object
Select vertice A (the yellow dot)
SHIFT+S, Cursor -> Selection
Select vertice A and equal number of vertices both from its left and right side
Delete them and you get a “square” hole
Repeat steps 4 and 5 on the opposite side of the object
Add a circle, which has as many vertices as the edge of the “square” hole
If needed, rotate the circle a little so that its top vertice moves to the highest position
Copy the circle (SHIFT+D) and move the copy to the opposite side
In the top view move the circles vertices so that the circle follows the shape of the object
In side view create faces that connect the circles and the edge of the “square” hole. In order to create a face, select either 4 vertices or 2 opposite edges and press F.
Select the vertices at the edge of the round hole (ALT+SHIFT+RMB)
Extrude them a few times, scale the extrusions down a little
Repeat steps 11 and 12 on the opposite side
Extrude the vertices to the opposite side
Mirror the selected points (S, extrusion axis, -1)
Dude you and Graybeard so rock! I spent like 2 hours trying to figure out how to do a dumb hole without success, mine looks beautiful now! Thanks a ton!
~Jo
P.S. The hole that I needed to make is for a job that I am doing so the time I wasted on it is non-paying work
You will save yourself so much effort by reading up on the retopo function in blender. It takes that 17 step process and cuts it down to:
1.go to the view you want the hold to be seen on.
2 add a circle as another object, with the desired amount of verts, in between your “view” and the object.
3. click retopo in the mesh editing panels
4. select all verts
5 hit g to grab
6 right click to cancel grab
7.extrude 2-3 times
8. unclick retop
9. join the objects
10. delete the verts of the cylinder that are under the circular mesh.
11. connect the meshes
Viola!! you now have a circle that has been “retopologized” (my word lol) to fit the curve of your cyclinder.
Quick notes on retopo tool. The verts will only be moved in the view you are working with. But watching that view will have you thinking it didn’t work. Check your other views. It worked! Only the verts being moved in the current view are effected (even if you cancel that action). Watch out for things like spot lights. I’ve noticed the retopo tool will actually place a vert on the “clip line” if its in the way. If your working in top view and want to add something to your charactors shoulders, simply hiding the head isn’t enough to have your new object conform to the shoulders…the head is still there and the verts of your new object will form around this “invisible” head. Niether is moving the head “20ft” straight up. Even though you view is now inbetween the head and the shoulders…retopo will still place those new verts on your head. If retopo doesn’t have the desired results…try a different view.
As I am trying to achieve a good looking visualization (and maybe animation) of the product, not a 100% precise cad model, Blender would do the job. Two good reasons to continue with Blender, but I still have two more. I said I want to learn Blender. I learn nothing if I give up. And Blender seems to have a good user community. I really appreciate your helpful and friendly attitude.
I spent like 2 hours trying to figure out how to do a dumb hole without success, mine looks beautiful now! Thanks a ton!