RTD4479

Ordered three MJT items ten ago and got them in three days.

MikeTrice

Posted 19 hours ago

The main model is done in Blender which a freebie but far from intuitive. Were I starting over again I would use Fusion 360 instead. The workflow I use is to produce a number of reference drawings in Inkscape (another freebie) and import them into Blender as a number of background images. The 3D model is then produced against these drawings and represents by far the majority of the effort. Once the model is ready to be printed it is exported as a .stl file which is then imported into Chitubox to be orientated and have the supports added. Chitubox then slices the model and supports which can be saved as a .photon file for the printer. Most times I actually do the following:

Export from Blender as .stl then open the stl in chitubox to add the support then save from chitubox as .stl again. Open the .stl file in Blender and edit it prior to reexporting the .stl which then goes back into chitubox o be sliced and the .photon file produced. The .photon file then gets opened in the Photon File Validator and has small unprintable islands removed and the "fixed" .photon file saved. This is finally sent to the printer. Phew, well you did ask!

Chitubox does have an automatic support generation option but usually I add them one at a time where I want them.

Thanks Mike - very informative and interesting.  I think you may have cured me of the desire to get into such things!

Regards,

Bob

Mike,

I must say the V2 body looks very good.  Forgive my ignorance but I have a question about the 3D process.  Are the extensive supports for the printed body added by a facility within the CAD system or print software, or are they something that you have to design in yourself?  If the latter, it presumably adds quite an overhead of time to the design process.

I'd like to get hold of a scrap Bachmann Mk1 suburban coach body.  Type, livery and external condition are not important as long as it the sides are intact, as I only need to cannibalise the lower sides for the chassis retaining lugs.  This is to fit inside etched sides as part of a conversion.  Reasonable expenses paid, but I don't need a complete coach. 

Thanks,

Bob

I'm not involved in the development of this model, hence my lack of response. I will, however, make a general comment which would apply to most 'OO' ready-to-run but is particularly relevant to those commissioning models, as there is inevitably at least one more financial margin to be built in to the cost chain. Even before design starts, it is necessary to decide the spec, and in this case it's a ready-to-run model to 'OO' gauge. Making it suitable to adapt to other gauges would add to the design time and cost, increasing the end price to everyone. Even if it wasn't too late to include in the design, such things all have a cost. It is unlikely that the 'OO' wheel sets could be opened out to EM gauge, so a complete new chassis would be needed, making it a very expensive way for EM modellers to obtain a locomotive body. (CJL)

Apologies - when you replied earlier that P4 clearance wasn't in the design spec I assumed you were involved somehow.

My point about all this was that a little more clearance within splashers of steam locos would facilitate quick wheel swap conversion, something which I believe EM folk do using spacing washers, although I'm not directly involved.  So no new chassis unless for another reason.

In my case, yes I would need a new chassis in P4 partly because I'd want to spring the loco, but I'd be prepared to lash out on the whole loco (as I have done many times before) because the body alone is worth having. A big saving in time over making and painting a kit body, and often as good if not better quality.  I was only suggesting a bit more clearance within splashers to make it easier.  My Hornby B17 needed so much taking off the inside of the rear splashers that they became like tissue paper and distorted.    Couldn't move them easily as they were moulded into the boiler.  

Anyway I don't want to carry on an argument which is going nowhere so I'll bow out at this juncture.

Justin, point taken about Peco but I wonder where this leaves us with the 16xx?  Wait and see if the wheels will fit I suppose.  If not, scrape and hope!

Regards,

Bob

That's a shame.  If it can't be converted then I'll have to build the SEF whitemetal kit, which is a lot of effort simply to get clearance in the splashers.  

 

Is it too late to include in the design?  it seems such a simple thing to ask for.

Well, no response so I'll take that as a no.

I'll close with one further point.  I see Peco have announced they will produce EM trackwork  - flexitrack and turnouts.  Evidently they believe there is a big enough market to justify the investment.  Might that give RTR manufacturers an opportunity to consider making the necessary small adjustments to new models to allow them to be more easily converted? With EM track becoming available, a little more clearance within splashers etc might lead to more sales...

It's not something that was in the spec. (CJL)

That's a shame.  If it can't be converted then I'll have to build the SEF whitemetal kit, which is a lot of effort simply to get clearance in the splashers.  

Is it too late to include in the design?  it seems such a simple thing to ask for.

The Scottish connection was an important consideration with the 16xx and I don't think it applies to any other pannier. Also the 'smallness' of the 16xx is in line with our previous releases (Sentinel, J70). I know the 'USA' isn't exactly small but its shape certainly made the mechanism a complex packaging exercise. (CJL)

A great choice and I'm keen to have one or maybe two.  But, following on from an earlier post, is there likely to be room within the splashers for P4 wheelsets?  Not a consideration for RTR I know, but does this make a big difference to the design/tooling?  Not a question I've asked before and I'll be interested to know.

No, this - and the previous F4/5/6 and J15 chassis are complete replacements and not designed to suit RTR chassis but kit built bodies (Gibson in both cases) - take a look at Rumney Models web site where you will find the instructions that set out the approach to assembly, from which you will be able to understand the construction of the kit/chassis and whether it suits your purpose. The 'trailing truck' in the F4/5/6 chassis kits are just that - independent trucks that replicate the behaviour of the radial truck design. Best look at the instructions to get the idea. IF we produce a kit for the N7 it will be a total replacement of the chassis.

 

Best,

Marcus

Thanks for that - I'd completely missed the F4/5/6 chassis on the Rumney web site, but there's no reason I'd have known.  Encouraging to know that these are a complete replacement chassis.

Regards,

Bob

It will be the same format as the F4/5/6 and J15 chassis - a fold up main assembly with CSB as the prime means of suspension. Of course it can be built rigid and ‘some’ consideration will be given to EM gauge, but as it is still in the very early planning stage I cannot commit to more. Once I get my hands on an Oxford product we can get more specific. Don’t expect anything this year and probably not until the summer of ‘19. I hope to be able to ‘fit’ it to the SE Finecast and Connoisseur kits too but its prime function is intended as a P4 conversion to the Oxford model. I am also hoping Andrew Jukes will release the GER 4’ 10” wheels once again to suit this and the J15.

Thanks for the information. Your design philosophy appears set so I am not going to try and persuade you away from CSBs, much as I'd like to.  I am not aware of the F4/5/6 and J15 designs as I am modelling GNR rather GER so do understand that what you are doing is along the lines of the Brassmasters P4 conversions which retain the RTR chassis?  I was hoping that a fold-up chassis may have few or no stretchers and might allow me to apply leaf springs fairly easily, but not if the RTR chassis is in the way.  In which case I will use what you provide.    What arrangement will you make for the trailing truck - will this have any form of springing?  I have a set of Sharman P4 drivers secreted away, having prised them out of Fox a few years ago, but the Exacto wheels will be superior and I think the omens are good that they will become available in due course.

‘Probably’ - as no design work has been done yet - we’ve only just got the etches for the J15 chassis - there is no reason why not. I’m in favour and I’m paying for it!

Just picked up on this and am very interested.  I have a SE Finecast chassis set aside for mine, but it's hardly state of the art.  Will you be designing the chassis to be sprung and, if so, leaf springing or CSBs?

Bob