I've been looking for a CAD-shaped package that is 'OBJ +MTL' friendly since I discovered that TurboCAD were not planning to add support. Worse, although they claimed to have added FBX support, their forum did not care to discuss its effectiveness. In fact, no-one on the forum seemed to have tried the facility, never mind noticed the small problem of rigging variation that currently besets Poser import.

A lot of the legacy / free modellers such as Carrara and Hexagon are stuck as x32, cannot cope with the hi-poly models and sets I want to rip or slice to Poser-friendly size. Blender's quirky UI gives me a prompt migraine...

So, sorta by default, I came to AC3D. It seemed to tick enough boxes, a complete home/student license would be cheaper than that dubious TurboCAD upgrade and it offered a fortnight's free trial.

So, after serendipitously de-bugging network render Box' CPU superfly settings, and belatedly installing my new all-in-one printer that's been on to-do list for several months, I down-loaded the AC3D pack.

First oops, Win'10 Defender refused to run the exe. Not watermarked or such. I set my totally paranoid Norton's to work, no dangers found...

Second oops, AC3D's 'Help' comes as a lonnnng web page. That is white text on black plus vivid blue section headings, so far so good.

But, the side-bar with index is dark gray text on black, barely legible. Well, D'uh...
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AC3D windows etc also had that too-gray on black text format, but the UI lets you change it. And makes that easy to do.

Now with an oven-meal heating, I quickly hunted  around my archives for some trial models. I needed something interesting to play with, something neither too simple or too complex for this first pass. A pair of potion / perfume bottles for DS, which I'd 'ripped' to OBJ seemed a good start. Unfortunately, they used 'DUF' calls per MC5/MC6 rather than eg JPGs.

Then, while browsing my archive of free downloads from ShareCG, AC3D recognised a .BLEND model. It read Blender ? Really ? Yes. And, unlike Blender itself, had a UI that made sense. Although the model, a low-poly 'Martian' ray-gun, lacked texture calls and was too simple to un-group to components, it readily exported to OBJ+MTL.

Fumbling through drop-down menus, I found the UV-mapping option I'd noticed earlier. Thirty seconds later, the defaults gave me a nice 1000x1000 auto-distributed template. A couple of minutes wielding a free Irfan View paintbrush produced a clunky JPG texture map. This hand-loaded okay, but adding 'map_Kd map1b.jpg' to the basic MTL using free Notepad made it automatic...

Not great art, but you can see progress from the Blender original, via default-gray mesh, its template and the result as OBJ+MTL...

Spent several hours playing with the boolean tools...

As yet, I've not found a way to take two 'bites' from an object and get what I want. Keeps producing 'not solids' with stray tris etc.

I think my test objects --standard AC3D primitives-- need a lot more polys to keep them as 'solid objects' rather than becoming 'open' shells with fewer boolean options.

Oh, and 'cutting tool' usually vanishes, so gotta remember to only use duplicates of those if may need again...

Funny enough, this was a pain in TurboCAD, too, as the legacy 'basic' modelling engine used closed surfaces, think shells, but the advanced modeller, which used solids, was much less friendly...

Oh, and yes, AC3D *will* read a texture-map call from an OBJ's MTL eg map_Kd 1_metal_rough.jpg but, so far, only for the first material it meets. Ignores rest. And only exports that one call. Okay if one (1) wrap-map invoked, such as my ray-gun example above, but I'll need to experiment with settings to see if have missed essential option beyond defaults....

Going to organise meal, then have another try.

Thank you kindly Nik

"Carrara and Hexagon are stuck as x32"

I thought Carrara 8.5 was 64-bit

"gray text on black, barely legible. Well, D'uh..."

gray on black, not a great idea of legibility

"so far, only for the first material it meets. Ignores rest."

So, a single texture map is the better approach? If I get around to this, then, I'll have to layer something in photoshop or PSP) is a bitmap graphics editor for computers running the Microsoft Windows operating system that was originally published by Minneapolis-based Jasc Software. In October 2004, Corel Corporation bought out Jasc software">paint shop pro & export it as a single texture map.

"Carrara and Hexagon are stuck as x32"

'I thought Carrara 8.5 was 64-bit '
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Yes, so it is !! Thank you, thank you !!

Has moved on from my DAZ freebie version. Must check for improved capacity and tool-set.

FWIW, if AC3D can only handle one (1) wrap-map or texture per exported object *and* has wonky Booleans, then is not better than my ~2017 TurboCAD. At least TC supports multiple 'colours' per model, one per part's 'drafting layer'. And TC would export such via 3DS format, which I could then 'texture by colour-codes' in eg Poser...

Snag is I want budget software able to reliably 'slice and dice' eg the vast, hugely complex OBJ+MTL sets by Richard Mandel and his team, free on SCG. Dozens of wrapped textures & colours, hundreds of texture calls...

I've spent entire evenings salvaging lesser models exported from FBX minus MTL, wearily matching the many nice textures to their oft-obscurely named materials. I think my record was ~70 materials, but that gave me a 3-day migraine. Worse, they never quite looked right, as lacked Ka, Kd, Ks etc modifiers beyond my 'best guess'...

I had a look at Richard Mandel's team's SCG profile. Great work by them      ! The models seem to have a lot of parts to them, "vast, hugely complex OBJ+MTL sets" as you mention. I see why it can take quite a bit of work to 'slice & dice'

Hi !

Could not get past the 'one texture-call per object' barrier, could not make those wretched Booleans behave.

Yes, AC3D can automatically 'UV' a clean mesh to a tidy template for off-line painting as a 'wrap-map'. That's real-neat, but still leaves AC3D with a 'glass ceiling'.

So, have un-installed prior to end of trial period.
         
And hunt resumes...

{ Sigh... }

FWIW, since I last checked, FreeCAD Org seem to have re-compiled their open-source package to x64, so I'll take a look...

Ah, no application is perfect, but we tip our hat & say "Well done!" to the ones that are good, especially the freeware ones & their producers    ! I downloaded & played (very little) with FreeCAD, & downloaded some books on how to use it, but have not yet gotten around to learning how to use it. I hope that you find the one that ones best for such a task, Nik .