Help With Animation

Support Animation and Rigging
1

I have been using AutoCAD 2000 for 20 years and I have just started using Blender, which is light years ahead of AutoCad 2000, so I have a lot of catching up to do. I have just started using Blender like a coupla weeks ago and I am trying to model a camshaft/lifter arrangement. I have created the camshaft with cams and used Boolean union to complete the camshaft assembly and added rotation to it. However, I cannot make the lifters move in sync with their respective cams (seen screenshots below). Image 1 shows the assembly in the start position. Image 2 shows the assembly with the camshaft rotated 180°. You can see that the lifters are not in sync with the camshaft. Can someone step me through the process of syncing the lifters to the camshaft? Remember, I am a noob and need exact step-by-step procedure? I would appreciate it very much.

Michael Lockett
Hot Springs AR

Attachments

Image 1.jpg543×648 20.3 KB

Image 2.jpg550×648 20.9 KB

2

First - Welcome to BA!

Second - you need a better title for your post, something like “Help Rigging a Cam and Cam Follower” - would attract the attention of the right people.

Third - you have not posted a blend file for us to look at what you have done, while you are on moderation (first 10 posts) upload them the pasteall.org/blends then post the link to your uploaded file here.

Fourth - you have cropped the Blender window, so we can’t see what you have been up to in regards settings, etc.

These point will help you get answers here as we don’t have to do some much guessing!

So now I have seen your post, this is one good way to rig a cam and valve setup:

Screen Shot 2017-05-01 at 13.48.52.png1245×777 217 KB

When you design a cam you always start off with a “flat” profile of where you want the follower in relation to the cam centre, then wrap this around the centre of the cam and you have your cam built.

I do exactly the same in Blender - start with the “flat” cam profile, get an empty to follow it, then use this to operate the armature. Then the rest is quite straight forward. :spin: (or maybe not…)

Here is the blend file - just press Play - you MUST check “Autorun Python Scripts” in User Preferences => File Tab or the drivers won’t work: cam.blend (580 KB) You may want to spend some time making small adjustments to the mesh profiles, I just did it approximately.

As you will notice - there is no easy way to do this, it is a complex operation for a first animation… :eyebrowlift:

Just let me know if I need to explain things further.

Cheers, Clock. :slight_smile:

EDIT:

You have found out quickly about Cyclic Dependency Loops - where one object is dependant upon another that is dependant upon the first - these don’t ever work and must be avoided…

AND:

Don’t use Booleans to create meshes like yours - just extrude and scale, booleans really screw up good topology - Blender is not CAD, it’s totally different (I too had to learn this coming from a CAD background)

3

Thank you for your response. Your cam assembly is way beyond my current knowledge of Blender. You’e talking way above my head. I’ve been using Blender for only a month or two and I got a lot to learn and few resources to learn from. However, I bought a book entitled ‘The Complete Guide to Blender Graphics’ by John M. Blain and am trying using that, but I still got a long way to go. Also, thanks for the link to pasteall.org/blender. That will be a good tool to use when I need more help.

Regards,

Michael in Hot Springs AR

4

You can always post blends here for us to look at and help you move forwards. If you are going to be doing mechanical models, I am happy to help as this is my area of speciality.

Rigging a crank & piston is the easiest part of an engine to start with, the valves are probably the hardest!!

Just ask here when you need some guidance.

Cheers, Clock

5

Thanks, everyone for responding to my post. Actually, I’m not trying to make an automobile camshaft/rocker/valve assembly. It’s part of a marble machine, but I thought I’d mention a camshaft/lifter assembly because it requires less description. I just thought the process would be the same.

The way it works is, at an arbitrary ‘start’ point, the shorter lifter will pick up a marble, 180° later in the cycle, the marble moves from the short lifter to the next one and so on. Every rotation, the short lifter will pick up a marble and the sequence continues as long as the camshaft is turning.

So that’s the plan. I’m looking for the simplest way to do this because I don’t know from ‘flat cam profile’ or ‘wrap around’ or getting ‘an empty to follow it’ or ‘cyclic dependency loops’ or any of that. Yes, I’m dumb, but weren’t aren’t we all at one time?

Blender file: http://pasteall.org/blend/index.php?id=46487

6

Very few people on here are “dumb” and you are not one of those. Learning a new software can be a long and tricky process, that’s why I said I would help you. I will look at your model over the next few days. I have a family death to deal with just now, so don’t expect too much too soon. Don’t get hung up on me using Blender terms, any you don’t understand I will explain, as I said earlier what you are trying to do is not a beginner exercise, but we can get there if you are prepared to learn and not get upset with me for using stuff you don’t know yet.

Cheers, Clock.

7

I am very sorry for your loss and hoping that things go well for you and your family. Thank you for responding and thank you for your help.

8

OK I have taken a look at your file. I see you have done the motion with Rigid Body Physics - this is really a very difficult path to travel!

You need to just make an Armature with some bones like I did, or even a simple IK chain to move the cam followers up and down. To move the marble, I would create a path for it using a Bezier curve and then animate the marble along the curve.

I know this seems like a simple exercise, but it is not a first animation issue - can I suggest you find Nathan Vegdahl’s “Humane Rigging” tutorials, or some basic mechanical tutorials to get you started. NV’s tutorials are for characters mainly, but they install a good discipline for rigging in any field. I will post you a blend file with a simple rising and falling “piston” type approach that will get you started either later today or later in the week, I have a lot on just now…

Cheers, Clock.

9

Is it possible that mlockitt216 wants the marbles to work with gravity?

10

Okay, thanks. In the meantime, I’ll check out Vegdahl’s tutorials.

11

Yes. The tops of the rectangular lifters are slanted inwards so that the marble, affected by gravity, will rest against the next lifter until it comes down far enough for the marble to transverse onto it, etc.