Kent Trammell (theluthier)

70 replies · posted

Citizen Collaboration: Modeling Heavy Equipment (Backhoe)

Accomplishing a BIG project TOGETHER

Starting in March 2020, I began a large stream project to model a comprehensive, highly-detailed Caterpillar 434E backhoe. Please watch the first stream (first 3 minutes of abridged version at least) for an overview.

It's a straight-forward project of building a complex model over an extended period of time. The spin on the project is that I want your help to accomplish it! If I build some parts and you build some parts, we will finish this thing much quicker. Plus the contribution format will include reviews, the potential of having your piece(s) assimilated into the final model. Not to mention large quantities of XP are at stake 🤑

NOTE: This is an involved project reserved for Citizen members.

Collaboration Details

The general idea is that I kickoff stages of the project via live stream, which is typically once per month. For the time in between streams, you choose a piece of the backhoe and apply what you learned from the stream to that piece. For example, the first stream covered initial block out. So between stream 1 and stream 2, your job is to pick a piece and block it out.

This is the repeating protocol for each assignment period (between-streams):

  1. Signing up for pieces of the model. I will be maintaining a Google Sheet to organize piece selection and grading. Following this URL will give you the ability to comment. The sheet is sectioned vertically and color-coordinated with a backhoe image. To sign up for a piece, right click on an empty cell below your desired piece section and click "Comment" (CTRL + ALT + M). Comment your name or username and I will fill it in officially as confirmation.

    Remember that it is OK for multiple people to model the same piece. But lets try to have at least one person assigned to each piece before doubling up.

    2. Submitting your piece for review. Exactly one week before the next stream is scheduled to be broadcast, your piece is due. In the "Attempt" cell of the spreadsheet, paste a download link to your .blend file via Dropbox, Google Drive, or equivalent hosting service. This will earn you at least 10 XP each week.

    3. Review. On stream I will review each submitted piece and decide which will be assimilated into the master model (in the case of multiple submissions of the same piece). The purpose of the review is to generate feedback for you work and advice for improvement.

    4. Assimilation. If your piece makes the cut and is assimilated into the master model, your name / username will be added to the object in Blender. You will go down in history as a definitive contributor to this epic backhoe model!

    Once the model is completely done, I plan to render a short demo reel showing off the model and crediting all contributors. It should be a rewarding conclusion to all the work we will do!

This is THE thread

We will centralize our collaborative communication between the streams and this thread. Ask any and all questions pertaining to the Backhoe project here.

Also I will reply to this thread after each stream with an assignment summary denoted by a  📣 emoji in the title. There I will clarify exactly what the expectations are for those contributing.

Let the building begin! 🚜

  • crew

    📣Assignment #1: Blockout Level 2

    March 19 - April 7th

    For the assignment period between stream 1 and stream 2 -  the goal is to upgrade my initial blockout (level 1) into a "level 2" blockout. My result from the stream is extremely simple with a lot of secondary pieces unaccounted for. I want you to continue the blockout approach with very simple geometry to accommodate for the secondary pieces. Here's what I mean as applied to the digger arm:

    Please resist the temptation to fully model any pieces for this first assignment. Remain within "blockout" range: Keep geometry simple while accounting for all the pieces that I left out at level 1.

    Everyone start from the same .blend file

    Download the MASTER_caterpillar-434e_model_blockout_01.blend file from the stream 1 page:

    Note: The file is packed with the modeling sheet and ref sheet.

    Please ask questions if anything about these instructions isn't clear! Otherwise let's get to work ✊

  • I Salute to you master. Lets make this thing Hurray!

  • Hands up if you want to build this

  • And we have some logos for the, hoe? I feel like that is not a nice word. 

  • don't copy it please don't

  • Cats are better than dogs.

    • oh I get it caterpillar builddozers

    • Here's what I have so far. I'm noticing some differences between the reference in the parking lot, and those from the brochure.
      Are we following the parking lot, or the brochure for consistency?

      Also blanchsb , we should probably collaborate closely on the part where my piece meets yours.

    • crew

      That's looking great ppfbourassa! A fine level 2 blockout to me.

      You bring up a good point about (in)consistency between the blueprint and the photo reference sheet (parking lot). The loader bucket in the parking lot has 2 additional pieces not featured in the blueprint:

      I wonder what those are for..I would say leave them out and follow the blueprint for consistency. They're kinda ugly in my opinion any way.

      I'm sure we'll run into many inconsistencies along the way that we'll need to sort out.

    • ppfbourassa Yeah I was thinking the same thing!I think it would be best for me to post the arms and connectors to you so that you can implement them onto your bucket. I actually started modeling the whole think on my own and noticed that Kent’s first blockout of the bucket comes too far back into those hinges. You’ll need to adapt it obviously.

      Also, I don’t think we need this level of detail yet but the forked-shovel piece on the bucket that swings open (with the hinge on the top of the loader bucket) is used to grab objects such as logs on the back end. It has some “teeth” on the back edge that helps it grab those objects.

      I am getting closer with my blockout but there are a lot of holes and pins on mine that I need to build in. I’m about 60% done. I’ll post a link when I am done.

    • Actually. I have enough to give you to work your part now. Gimme a sec and I will upload it.

    • blanchsb I'm not exactly sure what you mean. On the bottom part, which I'm calling Loader Bucket B, colored red here, did I address what you meant?

    • ppfbourassa Here’s what I was talking about. I may be getting ahead of the blockout with this comment but it is good to keep it in mind for later.

      I private messaged you with a link to the blend file I created with the Loader-Arms. That should be enough to get you going.

    • ppfbourassa  A couple more things to note: the back of the bucket ended up going too far back. I made a ”better” blockout to represent the contour a little better for reference in the file. You can delete it as I just wanted to point it out. I don’t think I got the supports exactly right but they are close enough to drive the point home.




    • blanchsb Yours is looking so good! Am I on the right track with the connections?

    • crew

      ppfbourassa blanchsb The collaboration between you too already is awesome! Both of your level 2 blockouts are looking sharp too. Excellent work so far 🤜💥🤛

    • ppfbourassa yeah that is looking great!

    • Okay here’s my updated loader arm progress. Made lots of holes and filled them with pins. Tried to maintain somewhat of decent topology for next stages around all of the holes and details.

    • crew

      Really nice work blanchsb! I'm wishing the next stream wasn't a month away...seeing you and ppfbourassa do work is making me impatient to continue the project!

    • Ok I am hitting a decent snag where reality clashes with reference. I wanted to get some community feedback/critique on my thought process.

      The lower hydraulic does not seem to fit based on the reference angle it is shown at

      I know the proportions are correct because I rotated the main loader arm in order to figure out the location for the lower support and also using a common reference bracket for it’s location.

      So, I just rotated everything and lined up to make sure I got close enough and I think I am going to push on with using the Red Dashed line (on the first image above) for where the hydraulic is supposed to go: My only concern is tire/wheel clearance where the main frame connects to the tire/wheel. Maybe I need to collaborate with spikeyxxx  as well since he offered the wheels???

      I’m going this route I think. The lower support is about midway along the loader arm and that would make most sense for load-bearing support while it is cantilevered in the air holding a “load”

    • theluthier blanchsb ppfbourassa 

      As far as I can tell from the reference pictures, thos two, ugly, additional pieces on the loader bucket are on all the pictures and seem very functional to me, although I 'm not sure what they are doing, I read them sort of like this:

      So they can be put in different positions...

    • blanchsb Are you saying the piston doesn't seem to point at the part it needs to connect to in the drawing? If that's the case, I'd say to follow your intuition, it's probably just a mistake in the illustration.

      Or are you saying there isn't enough room between the tire and the body for it to fit? That's trickier, because it looks to me like you are on the right track.

    • spikeyxxx My interpretation of this front area is that the base model has this rail going across so the user can add or modify the bucket to do any number things, and this particular reference has these metal bars attached because it's a function they needed.

      I could totally be wrong about this, but if they are added by an individual owner, I'd rather not include them in our model.

    • ppfbourassa You are probably right. I looked at some more reference online and did find pictures where there is nothing connected to that rail.

    • ppfbourassa yeah I am saying that it’s not pointing to the part it needs to connect to AND I’m a little concerned if I go with my gut and ditch the reference that the hydraulics will interfer on the back side of the wheel/tire where it connects to the axle

    • Gotcha,

      For what it's worth, I think you are correct on where it should connect, and how thin the axle is.

    • Those things are forklifts attached to the bucket, you can see where they can pivot on the top. and they are hold down with bolt on down.

    • Caterpillar people can do mods to their rides too

    • crew

      blanchsb kudos on your functional research and testing. I agree with your inclination to follow the red dashed line reroute. I've run into a few things with the blueprint that I know are inaccurate to the real thing. I trust your testing results 👍

    • crew

      Also I think I made the wrong call to omit the forklift brackets. All 4 official CAT brochures feature them. This is another strike against the blueprint's accuracy lol.

      Thanks to spikeyxxx and louhikarme for clearing up the mystery 👏

    • one thing i've learned when doing exact models of real things that blueprints are lacking, either because copyright stuff or that things have changed between different years of same manufacturer and then you also get reference pictures that might be on different model. So the more you have real reference pictures the better. 


    • louhikarme there is also the little issue that what we get are usually not the actual blueprints (I mean the technical drawings) like the ones they use to manufacture something.

      Anyway, a blueprint is just a copy of a drawing, so any drawing could be made in a blueprint. The naming is not incorrect, it just sounds more 'official' than it is.

      They make a drawing on transparent paper and then lay that on top of special paper with a light sensitive layer (which is yellow, by the way), shine a bright light over it so only where the lines are on the drawing the yellow layer stays. and then they fixate those lines with ammonia, which turns them blue. Hence the name;)

    • This is also worth mentioning the differences between a concept drawing or blueprint and a technical source-controlled-engineer-approved-drawing.

      Many sales catalogs fall short because they are built by Sales and Marketing departments. These departments don't interface on a daily basis with the engineering departments. So, naturally you get the "Silo" effect where one department posts stuff and then the other continues with trial and error development.

      I agree with louhikarme. Those forks rotate forward about the pivot bar on the top and turn the bucket into a fork-lift hybrid. Notice the forks get thinner at the bottom and thicker at the top. Ease of "stabbing" design.

    • and because of the ammonia part of it making blueprints stinks... 

  • Awww, Dang. You gotta be a citizen to download the files.

  • so who are you xenoslaywright 

  • theluthier I signed up for the Loader Arm

  • theluthier
    Quick Question,

    Anyway you could open up the project files for non citizens? 

    I'm asking because I'd love to collaborate (or at least try). 

  • so you are not a citizen Nahian Ilham (xenoslaywright) 

  • friends right

  • I am still interested in modeling that complex attachment-gizmo where the digger arm connects with the body of the machine, if no one else has claimed it yet.  It looks challenging and fun!

    I suppose can take another piece too, if that's too "small" of a component.

    • Hey jjakeblended , look at point 1 under the Collaboration Details above, there it says how you can enter your name for a certain part in the Google Sheet. There you can see what parts there are and which ones are already 'taken'.

    • crew

      jjakeblended It may be a small *scaled* piece compared to others, but it's not small in terms of complexity and detail. I'm OK with you doing that piece only. I'll put you down for "digger arm hinge".

  • I can't add my name to the list for the stabilizer.

  • I just noticed my piece is one side a battery box and stairs on the other. No symmetry for me. It seems to me the people that designed this thing knew I was going to get this part and made it so I couldn't use a mirror modifier. Thanks industrial designers.

  • Okay. I feel like I am done with the basic block out. Maybe I have gone farther than expected or maybe this is just right. I’m hoping it is far enough Because I am ready to move on to train some more. I have most mirror modifiers still active but there are 40+ objects so I don’t remember if I applied a couple on the more basic shapes.

    I’m including the wireframe and basic render here for feedback and critique. I tried my best to have clean topology to make it easy to add SubDiv Modifier(s) but there are probably areas that can be improved farther. There are a lot of circular cuts. I kept all circles at division of 8 and maintained same circle-rotation on pieces that shared a circle cutout.

    If this looks good enough then I will upload it to the Google Sheet. Hope everyone else is having as much fun as I did! Go DOGs!

    Wire Frame - Loader Arm Assembly

    Block Out - Loader Arm Assembly

    Reference and Playing Around

    Notice how the lower frame is cutting into the lower hydraulic. That will have to be thinned out to make room.

    I checked out the similar CAT machine at my work and there is plenty of Front Axle clearance behind the Front Wheels. There’s not a ton going on back there so I think the lower hydraulic shouldn’t interfere.

    ppfbourassa I’ll send you the updated file here shortly the same way I sent it before.

    • I posted the link via private message ppfbourassa but noticed that you already uploaded your to the Google Sheet. My bad.

      theluthier  I added a comment on my ”Attemp” row for the Loader Arm. When you get a free chance, let me know if you are able to download it just fine.

    • crew

      blanchsb You've crushed the blockout stage 2. Even a little further than I expected. Excellent work translating and interpreting the drawing + photos. The intersection of hydraulic + chassis blockout is going to be one of many things we'll need to solve. Thanks for making a note of it! And thanks for kicking off the collaboration with a bang 🤜💥🤛

      PS: I'm able to download your file fine 👌

  • I noticed  the wheel arches are not on the list. So I thought I would have a go. I added a comment and a link.

  • [Q] Do you want us to upload the entire scene like we downloaded with the collection for our part, or just the collection?

  • Here an augmented version of my wheels blockout level 2 with tyre treads:

    PS: I accidentally closed all but one tab (active tool seetings and workspace) in my properties editor. Does anyone of you know how to fix this?