For a while now, I have been messing with the fitting room from time to time. The clothes always looked fine, but when I posed the figure there would be major poke through and nothing I tried seemed to compensate. But today I tried it again, and when I was deciding what morphs to copy over, I included the four at the end. I didn't know what they even were, but the first one was mon pubis. (Yeah, I know! I looked it up.)

So when you convert clothing, should you always include those last 4 or only when the clothing covers that part. 

And was that why my clothing didn't fit when the poses changed...because I never include them before?

It depends on the clothing.  Pants, trousers, underwear, etc. may benefit if the morph is already present in the figure.  Dresses, skirts, long shirts, etc. not so much.  Another thing you could have tried is deleting the morph from the main figure and retrying the clothing fit.  If you find it's not necessary, it can be deleted.

After the fitting room use copy joints and copy morphs from the menu. 

The menu calls functions with better algorithms. Difference for morphs is greatest in P13, but for older versions that also was the advice. 

Thanks. I've been getting better results when I include that mon pubis and the glutes. I wonder why those are separate in the list instead of under the hips. Guess I won't need them for a shirt though. We'll see.

When transferring morphs, it is a good rule to extend the selection of one body part over what is necessary.  For example, when fitting a pair of shorts to a figure, include the abdomen and thighs or chest and shins.  

So what causes this?

I loaded L'homme and then the basket ball shorts. I positioned them around L'homme. Turned off IK. Zeroed him but not the clothing. Went to the fitting room and ran the fit. Looked good. Saved the clothing with the morphs added. Posed and then I saw that there were holes in the legs when I posed him. There were there before I posed him, but I couldn't see them. But they are not in the original clothing. Am I doing something wrong? Are the legs too close together, do I need to spread them a little and the clothing too before I fit? I've seen this on other clothing too. I hid the thigh just to make sure they were really holes and they were.

To whom do the shorts belong?  Are they dynamic or conforming?

M4. Conforming. But not conformed until after the fitting.

Check the mesh subdivision on the conforming shorts.  That may be part of the problem if the resolution is too low.  Reduce the number of iterations for the fit simulation.  Higher values cause unnecessary stretching.  You might need to constrain those parts most affected.  

Have you tried a close fit of the shorts and converted them to a prop first without running a fit simulation?  Afterward, perform a Fitting Room simulation with the prop and a conversion for L'Homme.  Or import the OBJ, save it as a prop then do the Fitting Room.  

I'm just throwing out some options you could try to make it work.

I just fitted a pair of M4 shorts on L'Homme without the issues that you are encountering.  Prefit the shorts in the Pose Room as close as possible to L'Homme.  Enter the Fitting Room and set your iterations to 15, method to prefit, and the weight value to 0.25.  Run your simulation and save the shorts as a figure.  Return to the Pose Room and conform the clothing to L'Homme.  

That's caused by the fabric of the inner thighs intersecting each other. I usually use the morph brush to push the inseam closer to the correct thighs before going to the fitting room

Thanks. I tried with your setting, Hborre but still had the holes. I moved L'homme's legs and the pants apart by 2% and that took care of the holes in the legs. But the crotch still had some holes. Maybe I'll try lowering them a tad.

Thanks, RedPhantom. I'll try that too.

Well, I finally got something without holes in the legs. I scaled the shorts up until there was no poke through any where. Checked that there was a gap between the legs. Ran the fitting. Saved the garment with the morphs I wanted. I did not select auto groups this time. Went back to the pose room. Conformed and move the legs. Did not see any holes.

Thanks.